Obscure one here guys. I was about 10 when I saw it, so 1993 ish, but may be a bit earlier or later.
I am in the UK but I think it was an American movie. I remember watching it on a Saturday night with my family, but it was definitely adult. A maverick psychology (or maybe philosophy) professor was terrorising his class of college students with a loaded revolver as a kind of experiment to test their reaction (but again I could be wrong). I vaguely remember them all being locked in the classroom and the test going wrong and people dying.
It may have been an episode of a serialised crime show or Tales from the Crypt or something but I don't think so, I thought it was a movie. I remember be