Continuity mistake: Benton is talking to Carla about her preganancy test and they go through the double doors to the snowy outdoors. Carla has nothing in her hand when she pushes the doors open, but once outside she is holding a hat - she wouldn't have even had time to pull it out of her pocket.
Continuity mistake: Dr. Hicks is standing in front of the surgery white board talking to Carter and she says "Care to join me?" He replies "Love to" and the shot goes right back to her - she has moved 8 or 10 inches to the left, without enough time to have done this in real life.
Continuity mistake: Carter is watching the clock, waiting for Peter to show up for a presentation. The clock jumps from 3:03 to 3:04 in a Split Second (we literally see the minute hand jump)but the second hand doesn't change posiiton.
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.