Let's start with the smaller -- totally gut-wrenching, but smaller -- storyline this week. Bailey and Derek are working together on a woman with a brain tumor. She has had surgeries before, and though Derek assures her she could live with her tumor for at least a few months, she opts to go forward with her surgery and also to sign DNR papers. Her husband is totally supportive, and they clearly have had long, happy lives together and seem to have the perfect marriage. (This is as opposed to Derek's divorce, etc. and Bailey's trying marriage counseling.) The surgery isn't successful, however, and when she flatlines, her husband crumbles and tries to literally keep her heart beating by himself. Derek has to step in when both the man and Bailey are too affected to let the woman die, and quietly and heartbreakingly, she goes.

Derek's annoyed with Meredith because she and Cristina are reading Ellis' diaries and talking about them late into the night, causing him to not get enough sleep. He enlists Sloane's, er... services, in that Mark will flirt with Cristina and hook up with her to keep her busy enough at night so that Mere will be quiet and Derek can then sleep. Cristina, however, is too busy competing to take part in a cool surgery. An unidentified patient comes in with a million things wrong, and she spends the day only trying to be the best for surgery. Alex and the interns are trying to get in practice so that they can show off as well, and they wind up working on unclaimed cadavers while George works on a weirdly realistic dummy that is presumably the one Izzie mentioned last week. Hunt is disgusted to see a) how personally involved with each other all the doctors are and b) how uncaring they seem to be about the patient, especially Cristina. But when he finally confronts her about it and basically calls her a heartless vulture, she explains what it was like to be with her dad when he died in a car accident and explains that's why she became a surgeon. He realizes he's totally wrong, and after earlier thinking he might quit, totally decides to stay on at Seattle Grace for a while.

Hahn has a heart patient coming in, who happens to be none other than the guy who would have gotten a heart over a year earlier... if Izzie hadn't stolen it from him. Izzie is paralyzed and can't do the job Hahn chose her to do, which is connect with the patient and help him through a risky procedure. She finds out that Izzie was responsible for the Denny Heart Debacle and goes to Richard to try and have her fired, but he won't do it and insists he took care of it and the situation is behind them. When they have to do the procedure a second time, she keeps Izzie on and forces her to do her job, and with the help of her visions of Denny, she's able to help the guy through it. It's not enough for Hahn, though. As she and Callie leave for the night, she's disgusted to hear Callie stand up for Izzie even a little bit. She tells Callie that she's reporting the incident to UNOS, and when Callie doesn't support the decision, tells her off for being only a sorta-lesbian, and leaves. It's only the second time we've really seen Erica have more than just one dimension to her personality, and yet at the same time, the argument is weirdly smooshed into one short scene that leads to Hahn's exit from the show forever. Except that it totally doesn't feel like that, we just know it from the news, and it means an otherwise pretty good episode ends on a fairly disconcerting note.