Visible crew/equipment: After Hayes asks Meredith if she knows Dr. Yang she avoids an answer and walks away, then when it cuts to Bailey as she walks toward Koracick, three tape marks (two red, one blue) are visible on the floor near Koracick. (00:36:30)
Continuity mistake: When Hunt and Warren are in the elevator, Warren is wearing normal clothes. When the storm into the O.R. Warren is suddenly wearing scrubs. There is no way he could have changed into scrubs fast enough to get to the room before they started cutting the bars off the guy on the table.
Continuity mistake: When Addison first comes to Seattle, she mentions that she likes Derek's hair. She says it's longer than usual, looks like Russell Crowe. In the flashback of the night he left his hair long like it always is. Actually it seems a little longer in the past than current.
Revealing mistake: When Alex is talking to Rebecca Pope at the end of the episode, we hear Alex say "Now I know more about you than my friends." Watch Rebecca's left eye on the right if the screen when she says, "That's pathetic." Someone did a bad job of editing the CGI and we see a phantom eye over her left eyebrow.
Other mistake: There are two mistakes when Grey is at the computer trying to figure out why her patient is having seizures. The camera pans out showing Bailey walking up - if you look at the computer it shows a login screen, but when Grey shows Bailey the screen it changes. Next one is when Grey blows up the pic of the taratoma - when they leave the picture on the computer it's actually a brain.
Continuity mistake: While Meredith and Izzie are in the kitchen discussing Derek, Izzie sets the freshly frosted whole chocolate cake on the counter, but when she takes a seat in the closeup there's a slice of cake already on the plate, and in following closeups the cake is either whole again or back with the cut slice. (00:39:45)
Continuity mistake: Avery and Kepner are at the bar. Keep looking between them (over Kepner's left shoulder). Right when Kepner says "I'm a soldier" a guy in in the background comes around the corner wearing a dark shirt with what looks like a red vest/sweater. The camera changes to a different angle for Avery's line, and then when it comes back to Kepner for her next line, the guy in the red sweater/vest comes around the corner again. (00:16:00)
Continuity mistake: Dixon is upset and rushes off. Bailey follows her into a room to calm her down. When Bailey enters we hear the sound of Bailey closing the door. In the next shot from Dixon's perspective the door is ajar 1-2 inches. Then the next shot from that angle the door is suddenly fully closed. (00:26:00)
Continuity mistake: In the scene between Preston Burke and Cristina Yang in the locker room, Dr. Burke walks in wearing a brown jacket. During the first shot the collar of his jacket is lying flat. After he starts talking, the collar is sticking up in the back. After he says "I know you," the shot zooms out and his collar is lying flat again. When he says "I know you" the second time, it is sticking up again until the scene ends. (00:27:30 - 00:28:30)