Continuity mistake: Romano is standing outside an ER room watching through the glass. To his left, down the hall, we can see a woman pushing someone in a wheelchair. But when the shot goes to him entering the room, there's an extra behind him on the left pushing a large cart of supplies - there was nowhere for him to come from.
Continuity mistake: Mark comes into the cafeteria with a sytrofoam bowl of something, and when he sits down he starts to take the lid off. The next shot shows him already eating it with a spoon - there was no time to accomplish this so quickly.
Continuity mistake: When the "accident" victims are brought in near near the start of the show, a woman wearing overalls is covered in masses of glistening blood in the closeup - but the wider shot shows less blood and it is much more dried on her clothing.
Continuity mistake: Lizzie sees Dr. Morgenstern for the first time in the ER and she asks Kerry, "Who the hell was that?", and Kerry answers, "Our Chief of Emergency Medicine." Yet when he resigns in Episode 19, he tells Peter he's resigning as Chief of Surgery. Unless he held both positions, Kerry's answer could not be considered a character mistake, as she would have known what his position was.
Continuity mistake: Near the beginning of the show, Peter is feeding Reese in the hospital cafeteria. Reese has a bowl of pablum that is in the middle of his high chair tray. The next shot shows the bowl way over to the left, even though there was no time for the change in position.
Continuity mistake: When Doug is sitting at the cafeteria with Mark, Peter and baby Reese, his arm is stretched out on the table as Peter says, "fifteen minutes of quality time". The shot changes and suddenly there is no sign of his arm.
Continuity mistake: Just before Peter bends over beside Reese, an extra is starting to walk behind them. The next shot shows the cereal on Peter's head and we should be able to still see the extra, but there's no sign of him.
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.