I originally conceived of this idea for an elevator a while ago. In my idea the mechanism also had a container for the severed arms. Actually, that was an idea for something to be seen in a live action movie. I think up weird stuff. Though I think it would be more useful for the subway because I hate it when people stick their arm in because they know the doors will be opened just long enough that they’ll be able to slip through. Also hate it when the doors are already open and someone gets into the doorway, and then yells up to their friend who still hasn’t come down the stairs because they walk so damn slow. I never want to be that person, so if you’re ever taking the subway with me, don’t make me be that person.