When House is about to inject morphine into Powell's body, the amount of morphine in the syringe changes between the shots. The syringe is half-full when House is shot from the front, and only a quarter full when he is shot from behind his left shoulder.
House's big tennis ball is red and purple in this episode. Later in the episode, the ball is gray and red.
When checking Mark (rhinovirus) in the examination room, the position of Dr. House's fingers changes. In the first shot, House's index finger is positioned above Mark's right eyebrow. The immediately following shot has the index finger positioned above the nose in the middle of the forehead. (Mark does not flinch in pain.)
In one shot, Dr. Powell is looking away from Cameron, but in the next, he's facing her.
After Dr. Powell was awakened from his artificial coma and refuses to be further tested for nerve damage, House secretly touches both of Powell's ankles and we can observe the left leg reacting. Directly after, walking the hall with Foreman and Chase, House talks about "no sensation in the left leg, abdomen, right arm".