diff --git a/strix/interface/tui/app.py b/strix/interface/tui/app.py
index 0987720..2b8f89b 100644
--- a/strix/interface/tui/app.py
+++ b/strix/interface/tui/app.py
@@ -751,7 +751,7 @@ class StrixTUIApp(App):  # type: ignore[misc]
             self.report_state.cleanup()
 
         def signal_handler(_signum: int, _frame: Any) -> None:
-            self._teardown_sandbox_blocking(timeout=10.0)
+            self._fire_sandbox_cleanup()
             self.report_state.cleanup(status="interrupted")
             sys.exit(0)
 
@@ -1705,36 +1705,24 @@ class StrixTUIApp(App):  # type: ignore[misc]
         )
 
     async def action_custom_quit(self) -> None:
-        await asyncio.to_thread(self._teardown_sandbox_blocking, timeout=10.0)
+        self._fire_sandbox_cleanup()
 
         if self._scan_thread and self._scan_thread.is_alive():
             self._scan_stop_event.set()
-            self._scan_thread.join(timeout=2.0)
 
         self.report_state.cleanup()
 
         self.exit()
 
-    def _teardown_sandbox_blocking(self, *, timeout: float) -> None:
+    def _fire_sandbox_cleanup(self) -> None:
         loop = self._scan_loop
         if loop is None or loop.is_closed():
             return
         run_name = self.scan_config.get("run_name")
         if not run_name:
             return
-        future = asyncio.run_coroutine_threadsafe(
-            session_manager.cleanup(run_name),
-            loop,
-        )
-        try:
-            future.result(timeout=timeout)
-        except TimeoutError:
-            logger.warning(
-                "Sandbox cleanup timed out after %.1fs; container may still be running",
-                timeout,
-            )
-        except Exception:
-            logger.exception("Sandbox cleanup failed")
+        with contextlib.suppress(Exception):
+            asyncio.run_coroutine_threadsafe(session_manager.cleanup(run_name), loop)
 
     def _is_widget_safe(self, widget: Any) -> bool:
         try:
diff --git a/strix/runtime/docker_client.py b/strix/runtime/docker_client.py
index fb6f680..2a75383 100644
--- a/strix/runtime/docker_client.py
+++ b/strix/runtime/docker_client.py
@@ -22,6 +22,7 @@ re-merging the parent body. Track upstream for an injection hook.
 
 from __future__ import annotations
 
+import contextlib
 import logging
 import uuid
 from typing import Any
@@ -34,6 +35,8 @@ from agents.sandbox.sandboxes.docker import (
     _manifest_requires_fuse,
     _manifest_requires_sys_admin,
 )
+from agents.sandbox.session.sandbox_session import SandboxSession
+from docker import errors as docker_errors  # type: ignore[import-untyped, unused-ignore]
 from docker.models.containers import Container  # type: ignore[import-untyped, unused-ignore]
 from docker.utils import parse_repository_tag  # type: ignore[import-untyped, unused-ignore]
 
@@ -121,3 +124,10 @@ class StrixDockerSandboxClient(DockerSandboxClient):
             image,
         )
         return container
+
+    async def delete(self, session: SandboxSession) -> SandboxSession:
+        container_id = getattr(getattr(session._inner, "state", None), "container_id", None)
+        if container_id:
+            with contextlib.suppress(docker_errors.NotFound, docker_errors.APIError):
+                self.docker_client.containers.get(container_id).kill()
+        return await super().delete(session)