Continuity mistake: In the episode where Elliot is missing J.D. and talking to him a lot on her phone, he asks her to drop the phone into Dr. Cox's pocket. She drops it into his left coat pocket, but he later pulls it out of his right coat pocket. He couldn't have changed it in his pocket, because he's surprised to find it.
Continuity mistake: Dr. Cox's stethoscope is hanging down more on his left side, but when he walks around to J.D. it is now hanging evenly around his neck. (00:21:40)
Continuity mistake: The woman in the wheelchair that Dr. Cox claims is dead is wearing glasses in some shots but not in others.
Continuity mistake: When Elliot and J.D are going up the stairs and J.D asks if they are racing, Elliot has a watch on her left hand, then in the next shot when they are racing, the watch is gone and doesn't reappear.
Continuity mistake: Right at the end, the shot shows Carla walking towards JD with a security guard in the background, the shot cuts to behind JD and suddenly the security guard has moved forward in position dramatically.
Continuity mistake: When JD is in the lift (elevator) with all the people and asks his patient if his gas is bad for the other people, the woman on the right has her arms crossed then in the next shot she has a single hand on her chest.
Continuity mistake: In the apartment there is a cardboard box on a table, with a strip of blue tape on it and a tube of paper sticking out of it. A few shots later another strip of blue tape suddenly appears on the box and the tube of paper has vanished. (00:02:35 - 00:03:15)
Continuity mistake: When Dr Cox is watching TV, a guy in green walks past the people in the background, the camera goes to a close up of the doctor with the remote and the same guy walks past again.
My Best Friend's Mistake - S1-E3
Continuity mistake: In the apartment, when they decide to watch "Fletch", there is a yellow cushion under J.D.'s right arm, sitting on the sofa. But it disappears between shots. (00:05:50)
My Best Friend's Mistake - S1-E3
Continuity mistake: Dr. Cox throws his white coat on the table and sits down, when he starts talking to Elliot the coat is now missing from the table. (00:16:40)
My Best Friend's Mistake - S1-E3
Continuity mistake: When Dr.Cox is Talking to Elliot before she leaves the room her name tag flips over and back again. (00:17:20)
My Old Lady - S1-E4
Continuity mistake: When J.D. picks up the granddaughter to blow out the candles on the cake, there are 3 candles placed at the front of the cake in the camera close up, but there weren't any before he picked her up. (01:17:35)
My Old Lady - S1-E4
Continuity mistake: The heart monitor lines change a few times, from being close to the neck going straight back, to going around the right side of the pillow. (01:25:50 - 01:26:50)
My Old Lady - S1-E4
Continuity mistake: When JD is at the birthday party, watch the chocolate on his face. At one point there are two separate bits of chocolate on his left cheek, then the shot changes and they are gone. The shot changes again and they are back.
Continuity mistake: When Turk and Elliott are in the line at the cafeteria, you can see that Turk has two plates on his tray and Elliott has a juice box on her tray. When they turn around at the end of the line Turk has just one plate on his tray and the juice box on Elliott's tray is also gone.
Continuity mistake: When the janitor is speaking into the stethoscope, his right elbow is on his knee and his left hand is on the mattress, when it cuts closer, his elbow is further up and his hand is next to his leg.
Continuity mistake: While Turk is talking to Carla the clock behind Turk changes from 1:18 to 1:25 back to 1:18 and then to 1:32 in a minutes time. (02:48:45 - 02:49:45)
Answer: Dan was drinking beer and Cox feared that Dan might get so intoxicated he would fall asleep and drown in the tub.
Mortug