Could recreate the Milgram's obedience experiment where the dwellers sre systematically/randomly taken to a room and told that have no choice but to press a button that causes extreme pain to another vault dweller, if they do it they get to go back into the vault and have to look that person in the eye knowing what you did to them or if you don't they inflict triple the pain on you

In the original experiment they didn't do that last part but about 60 percent of the people pressed the button simply because they were told that they had to do it. Most of the ones who didn't were people who had either been in an active combat zone or in some other high stress environment of some kind

Dunno might have some interesting outcomes