@Kolanaki @The_Picard_Maneuver That is, when my teammate really wanted to use a bag of 1K ball bearings to trip up opponents on the other side of a door, we made sure the door was locked first from our side, dumped the ball bearings, then unlocked the door (It helped that it needed a special item on a pedestal to unlock the door.).

Then it made sense that they worked as they did.