diff --git a/examples/debugging/multi_nested_subactors_error_up_through_nurseries.py b/examples/debugging/multi_nested_subactors_error_up_through_nurseries.py
index 6cfce50f..fe50d9a4 100644
--- a/examples/debugging/multi_nested_subactors_error_up_through_nurseries.py
+++ b/examples/debugging/multi_nested_subactors_error_up_through_nurseries.py
@@ -1,3 +1,5 @@
+from functools import partial
+
 import trio
 import tractor
 
@@ -21,25 +23,36 @@ async def breakpoint_forever():
 async def spawn_until(depth=0):
     """"A nested nursery that triggers another ``NameError``.
     """
-    async with tractor.open_nursery() as n:
+    async with (
+        tractor.open_nursery() as an,
+        trio.open_nursery() as tn,
+    ):
         if depth < 1:
 
-            await n.run_in_actor(breakpoint_forever)
-
-            p = await n.run_in_actor(
-                name_error,
-                name='name_error'
+            tn.start_soon(
+                partial(
+                    tractor.to_actor.run,
+                    breakpoint_forever,
+                    an=an,
+                )
             )
+
             await trio.sleep(0.5)
             # rx and propagate error from child
-            await p.result()
+            await tractor.to_actor.run(
+                name_error,
+                an=an,
+                name='name_error',
+            )
 
         else:
             # recusrive call to spawn another process branching layer of
-            # the tree
+            # the tree; blocks (up) each level until the leaf's
+            # `name_error` relays through.
             depth -= 1
-            await n.run_in_actor(
+            await tractor.to_actor.run(
                 spawn_until,
+                an=an,
                 depth=depth,
                 name=f'spawn_until_{depth}',
             )
@@ -65,35 +78,34 @@ async def main():
              └─ python -m tractor._child --uid ('spawn_until_0', 'de918e6d ...)
 
     """
-    async with tractor.open_nursery(
-        debug_mode=True,
-        loglevel='pdb',
-    ) as n:
-
-        # spawn both actors
-        portal = await n.run_in_actor(
-            spawn_until,
-            depth=3,
-            name='spawner0',
+    async with (
+        tractor.open_nursery(
+            debug_mode=True,
+            loglevel='pdb',
+        ) as an,
+        trio.open_nursery() as tn,
+    ):
+        # spawn both spawner trees as concurrent one-shots; the
+        # first tree's (relayed) error cancels the other.
+        tn.start_soon(
+            partial(
+                tractor.to_actor.run,
+                spawn_until,
+                an=an,
+                depth=3,
+                name='spawner0',
+            )
         )
-        portal1 = await n.run_in_actor(
-            spawn_until,
-            depth=4,
-            name='spawner1',
+        tn.start_soon(
+            partial(
+                tractor.to_actor.run,
+                spawn_until,
+                an=an,
+                depth=4,
+                name='spawner1',
+            )
         )
 
-        # TODO: test this case as well where the parent don't see
-        # the sub-actor errors by default and instead expect a user
-        # ctrl-c to kill the root.
-        with trio.move_on_after(3):
-            await trio.sleep_forever()
-
-        # gah still an issue here.
-        await portal.result()
-
-        # should never get here
-        await portal1.result()
-
 
 if __name__ == '__main__':
     trio.run(main)
diff --git a/examples/debugging/multi_subactor_root_errors.py b/examples/debugging/multi_subactor_root_errors.py
index 31bb7dd1..56f217b4 100644
--- a/examples/debugging/multi_subactor_root_errors.py
+++ b/examples/debugging/multi_subactor_root_errors.py
@@ -16,11 +16,11 @@ async def spawn_error():
     """"A nested nursery that triggers another ``NameError``.
     """
     async with tractor.open_nursery() as n:
-        portal = await n.run_in_actor(
+        return await tractor.to_actor.run(
             name_error,
+            an=n,
             name='name_error_1',
-            )
-        return await portal.result()
+        )
 
 
 async def main():
@@ -38,29 +38,36 @@ async def main():
         - root actor should then fail on assert
         - program termination
     """
-    async with tractor.open_nursery(
-        debug_mode=True,
-        loglevel='devx',
-    ) as n:
+    async with (
+        tractor.open_nursery(
+            debug_mode=True,
+            loglevel='devx',
+        ) as an,
+        trio.open_nursery() as tn,
+    ):
+        # spawn both actors..
+        portal = await an.start_actor(
+            'name_error',
+            enable_modules=[__name__],
+        )
+        portal1 = await an.start_actor(
+            'spawn_error',
+            enable_modules=[__name__],
+        )
 
-        # spawn both actors
-        portal = await n.run_in_actor(
-            name_error,
-            name='name_error',
-        )
-        portal1 = await n.run_in_actor(
-            spawn_error,
-            name='spawn_error',
-        )
+        # ..and bg-schedule their erroring tasks.
+        tn.start_soon(portal.run, name_error)
+        tn.start_soon(portal1.run, spawn_error)
+
+        # yield to the bg tasks so both RPC requests are
+        # submitted (and start crashing) before the root's own
+        # error below (the legacy `run_in_actor()` submitted
+        # in-line with each spawn).
+        await trio.sleep(0.5)
 
         # trigger a root actor error
         assert 0
 
-        # attempt to collect results (which raises error in parent)
-        # still has some issues where the parent seems to get stuck
-        await portal.result()
-        await portal1.result()
-
 
 if __name__ == '__main__':
     trio.run(main)
diff --git a/examples/debugging/multi_subactors.py b/examples/debugging/multi_subactors.py
index 57634cc3..79775053 100644
--- a/examples/debugging/multi_subactors.py
+++ b/examples/debugging/multi_subactors.py
@@ -18,11 +18,11 @@ async def spawn_error():
     """"A nested nursery that triggers another ``NameError``.
     """
     async with tractor.open_nursery() as n:
-        portal = await n.run_in_actor(
+        return await tractor.to_actor.run(
             name_error,
+            an=n,
             name='name_error_1',
         )
-        return await portal.result()
 
 
 async def main():
@@ -36,17 +36,39 @@ async def main():
     `-python -m tractor._child --uid ('spawn_error', '52ee14a5 ...)
        `-python -m tractor._child --uid ('name_error', '3391222c ...)
     """
+    errors: list[BaseException] = []
+
     async with tractor.open_nursery(
         debug_mode=True,
         # loglevel='runtime',
-    ) as n:
+    ) as an:
 
-        # Spawn both actors, don't bother with collecting results
-        # (would result in a different debugger outcome due to parent's
-        # cancellation).
-        await n.run_in_actor(breakpoint_forever)
-        await n.run_in_actor(name_error)
-        await n.run_in_actor(spawn_error)
+        async def run_and_collect(fn):
+            '''
+            One-shot whose (boxed) error is stashed instead of
+            raised so a sibling's crash never cancels the others
+            before they've had their own debugger sessions (the
+            "collect all errors" the legacy `run_in_actor()` API
+            did implicitly at nursery teardown).
+
+            '''
+            try:
+                await tractor.to_actor.run(fn, an=an)
+            except tractor.RemoteActorError as rae:
+                errors.append(rae)
+
+        # Spawn all one-shot task actors, collecting (vs.
+        # raising) their errors.
+        async with trio.open_nursery() as tn:
+            tn.start_soon(run_and_collect, breakpoint_forever)
+            tn.start_soon(run_and_collect, name_error)
+            tn.start_soon(run_and_collect, spawn_error)
+
+        if errors:
+            raise BaseExceptionGroup(
+                'multi_subactors errored!',
+                errors,
+            )
 
 
 if __name__ == '__main__':
diff --git a/examples/debugging/root_cancelled_but_child_is_in_tty_lock.py b/examples/debugging/root_cancelled_but_child_is_in_tty_lock.py
index 93daa33b..083a7fb3 100644
--- a/examples/debugging/root_cancelled_but_child_is_in_tty_lock.py
+++ b/examples/debugging/root_cancelled_but_child_is_in_tty_lock.py
@@ -1,3 +1,5 @@
+from functools import partial
+
 import trio
 import tractor
 
@@ -10,14 +12,14 @@ async def name_error():
 async def spawn_until(depth=0):
     """"A nested nursery that triggers another ``NameError``.
     """
-    async with tractor.open_nursery() as n:
+    async with tractor.open_nursery() as an:
         if depth < 1:
-            # await n.run_in_actor('breakpoint_forever', breakpoint_forever)
-            await n.run_in_actor(name_error)
+            await tractor.to_actor.run(name_error, an=an)
         else:
             depth -= 1
-            await n.run_in_actor(
+            await tractor.to_actor.run(
                 spawn_until,
+                an=an,
                 depth=depth,
                 name=f'spawn_until_{depth}',
             )
@@ -37,28 +39,33 @@ async def main():
        └─ python -m tractor._child --uid ('name_error', '6c2733b8 ...)
 
     '''
-    async with tractor.open_nursery(
-        debug_mode=True,
-        enable_transports=['uds'],  # TODO, apss this via osenv?
-        loglevel='devx',  # XXX, required for test!
-    ) as n:
+    async with (
+        tractor.open_nursery(
+            debug_mode=True,
+            enable_transports=['uds'],  # TODO, apss this via osenv?
+            loglevel='devx',  # XXX, required for test!
+        ) as an,
+        trio.open_nursery() as tn,
+    ):
+        # spawn the deeper tree in the bg..
+        tn.start_soon(
+            partial(
+                tractor.to_actor.run,
+                spawn_until,
+                an=an,
+                depth=1,
+                name='spawner1',
+            )
+        )
 
-        # spawn both actors
-        portal = await n.run_in_actor(
+        # ..while blocking on the shallow (faster to fail) tree
+        # whose propagated error triggers nursery cancellation.
+        await tractor.to_actor.run(
             spawn_until,
+            an=an,
             depth=0,
             name='spawner0',
         )
-        portal1 = await n.run_in_actor(
-            spawn_until,
-            depth=1,
-            name='spawner1',
-        )
-
-        # nursery cancellation should be triggered due to propagated
-        # error from child.
-        await portal.result()
-        await portal1.result()
 
 
 if __name__ == '__main__':
diff --git a/examples/debugging/root_timeout_while_child_crashed.py b/examples/debugging/root_timeout_while_child_crashed.py
index 4dfc699d..28cb2cf8 100644
--- a/examples/debugging/root_timeout_while_child_crashed.py
+++ b/examples/debugging/root_timeout_while_child_crashed.py
@@ -13,17 +13,24 @@ async def main():
     simultaneously.
 
     '''
-    async with tractor.open_nursery(
-        debug_mode=True,
-        # loglevel='debug'  # ?XXX required?
-    ) as n:
-
-        # spawn both actors
-        portal = await n.run_in_actor(key_error)
+    async with (
+        tractor.open_nursery(
+            debug_mode=True,
+            # loglevel='debug'  # ?XXX required?
+        ) as n,
+        trio.open_nursery() as tn,
+    ):
+        # spawn the actor..
+        portal = await n.start_actor(
+            'key_error',
+            enable_modules=[__name__],
+        )
         print(
             f'Child is up @ {portal.chan.aid.reprol()}'
         )
-
+        # ..then schedule its erroring task in the bg while the
+        # root blocks below.
+        tn.start_soon(portal.run, key_error)
 
         # XXX: originally a bug caused by this is where root would enter
         # the debugger and clobber the tty used by the repl even though
diff --git a/examples/debugging/shielded_pause.py b/examples/debugging/shielded_pause.py
index e6df907c..190374ca 100644
--- a/examples/debugging/shielded_pause.py
+++ b/examples/debugging/shielded_pause.py
@@ -75,10 +75,10 @@ async def main():
     async with tractor.open_nursery(
         debug_mode=True,
     ) as n:
-        portal: tractor.Portal = await n.run_in_actor(
+        await tractor.to_actor.run(
             cancelled_before_pause,
+            an=n,
         )
-        await portal.wait_for_result()
 
         # ensure the same works in the root actor!
         await pm_on_cancelled()
diff --git a/examples/debugging/subactor_breakpoint.py b/examples/debugging/subactor_breakpoint.py
index 67a5b7e0..33b16154 100644
--- a/examples/debugging/subactor_breakpoint.py
+++ b/examples/debugging/subactor_breakpoint.py
@@ -19,10 +19,12 @@ async def main():
         loglevel='cancel',
     ) as n:
 
-        portal = await n.run_in_actor(
+        # parks awaiting a result which only arrives once the
+        # user quits (`BdbQuit`s) the child's REPL loop.
+        await tractor.to_actor.run(
             breakpoint_forever,
+            an=n,
         )
-        await portal.wait_for_result()
 
 
 if __name__ == '__main__':
diff --git a/examples/debugging/subactor_error.py b/examples/debugging/subactor_error.py
index fabdcedb..95c1fe12 100644
--- a/examples/debugging/subactor_error.py
+++ b/examples/debugging/subactor_error.py
@@ -12,16 +12,12 @@ async def main():
     ) as an:
 
         # TODO: ideally the REPL arrives at this frame in the parent,
-        # ABOVE the @api_frame of `Portal.run_in_actor()` (which
-        # should eventually not even be a portal method ... XD)
+        # ABOVE the @api_frame of `to_actor.run()` ..
         # await tractor.pause()
-        p: tractor.Portal = await an.run_in_actor(name_error)
 
-        # with this style, should raise on this line
-        await p.wait_for_result()
-
-        # with this alt style should raise at `open_nusery()`
-        # return await p.wait_for_result()
+        # the one-shot blocks on the subactor's result so the
+        # boxed `NameError` raises right here.
+        await tractor.to_actor.run(name_error, an=an)
 
 
 if __name__ == '__main__':
diff --git a/examples/debugging/sync_bp.py b/examples/debugging/sync_bp.py
index 8c4ba6e9..c22f0fff 100644
--- a/examples/debugging/sync_bp.py
+++ b/examples/debugging/sync_bp.py
@@ -90,7 +90,7 @@ async def main() -> None:
 
         # TODO: 3 sub-actor usage cases:
         # -[x] via a `.open_context()`
-        # -[ ] via a `.run_in_actor()` call
+        # -[ ] via a `to_actor.run()` call
         # -[ ] via a `.run()`
         # -[ ] via a `.to_thread.run_sync()` in subactor
         async with p.open_context(
diff --git a/tests/devx/test_debugger.py b/tests/devx/test_debugger.py
index dfcf36d8..e2b803aa 100644
--- a/tests/devx/test_debugger.py
+++ b/tests/devx/test_debugger.py
@@ -849,43 +849,36 @@ def test_multi_nested_subactors_error_through_nurseries(
             break
 
     # boxed source errors
+    #
+    # NB post-#477 (`to_actor.run()` one-shots in local
+    # task-nurseries) the final relay is the LAST-released
+    # (leaf) REPL's error chain: it wins each level's
+    # relay-vs-cancel race so every level's single-member
+    # group gets unwrapped by the runtime's `collapse_eg()`
+    # (annotated at each actor boundary) while the sibling
+    # tree ('spawner1') is cancelled + absorbed. The legacy
+    # `run_in_actor()` teardown-reap instead grouped BOTH the
+    # `name_error` and bp-quit chains into the final dump
+    # (the previously-unexplained "extra" patterns).
     expect_patts: list[str] = [
-        "NameError: name 'doggypants' is not defined",
         "tractor._exceptions.RemoteActorError:",
-        "('name_error'",
 
-        # first level subtrees
-        # "tractor._exceptions.RemoteActorError: ('spawner0'",
-        "src_uid=('spawner0'",
-
-        # "tractor._exceptions.RemoteActorError: ('spawner1'",
-
-        # propagation of errors up through nested subtrees
-        # "tractor._exceptions.RemoteActorError: ('spawn_until_0'",
-        # "tractor._exceptions.RemoteActorError: ('spawn_until_1'",
-        # "tractor._exceptions.RemoteActorError: ('spawn_until_2'",
-        # ^-NOTE-^ old RAE repr, new one is below with a field
-        # showing the src actor's uid.
-        "src_uid=('spawn_until_2'",
+        # each level's unwrapped-single-member-group
+        # annotation + the first-level subtree's boundary
+        # footer.
+        "( ^^^ this exc was collapsed from a group ^^^ )",
+        "------ ('spawner0'",
     ]
-    # XXX, I HAVE NO IDEA why these patts only show on the
-    # `trio`-spawner but it seems to have something to do with
-    # what gets dumped in prior-prompt latches somehow??
-    # TODO for claude, explain and or work through how this is
-    # happening but ONLY WHEN RUN FROM THE TEST, bc when i try to
-    # run the test script manually the correct output ALWAYS seems
-    # to be in the last `str(child.before.decode())` output !?!?
     if (
         not is_forking_spawner
         and
         last_send_char == 'q'
     ):
         expect_patts += [
-            # expect the pdb-quit exc.
+            # expect the pdb-quit exc relayed from the leaf's
+            # bp-loop child.
             "bdb.BdbQuit",
-            # BUT WHY these dude!?
-            "src_uid=('spawn_until_0'",
-            "relay_uid=('spawn_until_1'",
+            "src_uid=('breakpoint_forever'",
         ]
 
     assert_before(