Continuity mistake: When Peter and Jeanie are outside talking about their test results, there is an extra in a green sweater behind them who covers more ground than humanly possible from one shot to the next.
Continuity mistake: When Peter goes to his sister's picnic, he puts a pink box on the table and then sits in front of it. When his attention is diverted by a woman, suddenly the box is in front of him.
Continuity mistake: Carter is doing a nasogastric intubation on a emergency patient and suddenly the patient violently pukes blood all over Carter's medical gown, his throat and the lower part of the face, then a quick shot of the stunned nurses, and when Carter is shown again he is perfectly clean.
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.