Other mistake: When the patient Isadore is brought in, early in the show, he is transferred from the stretcher onto a table, and we can see him deliberately move his right hand out of the way of the other actors moving him. He is supposed to be unconscious and very seriously injured so would not have done this is real life.
Continuity mistake: Susan and nurse Connie are talking to the fraudulent doctor - Susan has her clipboard at waist level and is lifting one page up with her right hand. The next shot shows her holding the clipboard down at hip level and both hands are on it. There was not enough time for the change.
Continuity mistake: Carter, referring to the patient Isadore, announces that he can't find a pulse in his leg - as he says this, his stethoscope is around his neck. Doug orders him to find a surgeon and suddenly the stethoscope is in Carter's ears, but there was no time for the switch.
Continuity mistake: Doug introduces his girlfriend's son Jake to old girlfriend Linda who is holding her coat over her arm with her hands clasped together. As she says hello to Jake she puts her hand up to her hair, but from his angle we still see her hands together. This continues for the next couple of shots as they chat.
Answer: A man named Paul Sobriki comes into the ER in the season 6 episode 13 " All in the Family." He is complaining of headaches, Carter and Lucy decide to rule out meningitis and do a lumber puncture. Paul struggles during the procedure and believes that both doctors are stabbing him. Lucy, who is interested in Psych thinks something is wrong with their patient mentally, but Carter is dismissive of her. She gets cross with his attitude and she calls the psych department anyway to have a look at him. Later on and near the closing 20 minutes or so of the episode, all the staff start playing loud music and get a cake which appears to be blue lol, together to party as it's Valentines Day, Carter returns from somewhere and asks where Lucy is. He goes to check one of the rooms for her and Paul Sobriki comes up behind him in the dark and stabs him twice in the lower back, he collapses and as he falls unconscious he sees Lucy on the ground also. In the next episode, Be Still My Heart (ep 14), Dr Weaver discovers them and all of the staff work to try and save them, whilst Carter survives. Lucy's wounds are fatal and suffers a pulmonary embolism as Corday and Romano try to save her. Carter is grief stricken and feels guilty about the way he treated her, he becomes addicted to painkillers and Benton, Greene all help him and book him into rehab.