Sounds like a bit of an idiot to me for the way he reacted - it's only 20 minutes and it manners to stay if you all agreed that you were playing until 2 am. Fair enough if he lost all his budget he may as well leave, but he didn't. It also depends on how binding your agreement was, and perhaps he had thought he could leave whenever? House rules like that should be stated clearly, but in the long-term it sounds like you don't want to invite that guy back!