Being attracted to someone that you normally would not even glance at because they are in your med school class with you. The main cause of this attraction is being cooped up with the same people day after day. This makes you look at people in a different way. Kind of like being in prison, where you might be straight, but you might have sex with some feminine guy because that is your only option in the pen. Med school is strikingly similar.
Med student #1: Man, Jenny is pretty hot.
Med student #2: Wow, she is not hot at all, if you saw her out in the real world you wouldn't even give her a second look. She is just med school hot.