Continuity mistake: While Carla's brother eats his chips, his hands move from left to right while holding the bag through out the scene. (00:09:00 - 00:09:35)
Revealing mistake: J.D visits Danni's apartment to talk to her about Elliot. The guy who answers the door says 'I better put on some underwear' but when he walks away you can see that he is wearing boxer shorts.
Answer: Dan was drinking beer and Cox feared that Dan might get so intoxicated he would fall asleep and drown in the tub.
Mortug