The thing about insanity jokes is that you can’t let the reader see them coming or they flop.  It’s also well-trodden joke territory in general, so you have to do something beyond the “ha ha there’s a crazy guy” to make them work.  What I tried doing here was to let the reader all of a sudden see it from the perspective of the orderly behind that door.  I don’t plan on doing a lot of insanity jokes.