diff --git a/container_manager.py b/container_manager.py
index abd8a9f..3f7e686 100644
--- a/container_manager.py
+++ b/container_manager.py
@@ -143,6 +143,11 @@ def wrapper_run_command(self, *args, **kwargs):
 
     @run_command
     def kill_expired_containers(self, app: Flask):
+        # Handle both scheduled and manual calls
+        if not isinstance(app, Flask):
+            from CTFd import create_app
+            app = create_app()
+
         with app.app_context():
             containers: "list[ContainerInfoModel]" = ContainerInfoModel.query.all()
 
diff --git a/models.py b/models.py
index 4ea536c..0571ada 100644
--- a/models.py
+++ b/models.py
@@ -64,7 +64,7 @@ class ContainerFlagModel(db.Model):
     )
     container_id = db.Column(
         db.String(512),
-        db.ForeignKey("container_info_model.container_id"),
+        db.ForeignKey("container_info_model.container_id", ondelete="CASCADE"),
         nullable=True,
     )
     flag = db.Column(db.Text)
diff --git a/user_routes.py b/user_routes.py
index 3ee8ade..c7497a9 100644
--- a/user_routes.py
+++ b/user_routes.py
@@ -88,7 +88,7 @@ def route_stop_container():
             user_id=None if is_team_mode() else xid
         ).first()
 
-        if running_container:
+        if running_container and running_container.container_id:
             return kill_container(container_manager, running_container.container_id)
         return {"error": "No container found"}, 400
     except ValueError as err: