Miranda's husband is fed up because she's never home now that she's Chief Resident. He insists they talk so she tells him to come by the hospital for lunch.
Meredith wants to tell Derek she doesn't want him dating anyone else, but can't bring herself to do it. Derek asks Rose about the ring she wears on a chain around her neck and she says it's a ring from an engagement that ended a year ago. Derek looks thoughtful as she says it ended because she knew what she wanted and her ex-fiance didn't.
An ambulance loses control after the driver has a seizure and crashes into another ambulance already parked outside the hospital. One of the ambulance attendants refuses Miranda's help, insisting he'll wait for a male doctor, but when Richard tries to examine him, he wants to wait for a "different" doctor. Richard realizes the man wants a white doctor and orders Miranda to deal with the situation.
Depressed about her lack of chemistry with George, Izzie is looking to get on a "hardcore cardio" rotation with Erica, but when she pays more attention to a patient's young daughter than the patient himself, Erica tells her she doesn't need her services for the day.
One of the paramedics, Stan, has his legs stuck in the doors of the ambulance after the accident. He asks Richard to find his wife and Richard tells Meredith it's going to be for Stan to say goodbye: Once they move him, he'll bleed out and there's nothing they can do to save him. Richard asks the other paramedic, Ray, who's hanging upside down in the wrecked ambulance, to keep talking to Stan until his wife shows up. She arrives in time to say goodbye and then it's time to separate the two ambulances. Ray and Stan hold hands but Stan doesn't survive. Now that they have a clear path to Ray, they can see that the oxygen tank is imbedded in his back. They'll have to do an ultrasound to see if they can remove it and Meredith volunteers. Ray freaks out and Meredith promises him he won't die today.
A man with an infected chest -- who also has shrapnel in his leg after the ambulance crash -- is upset that his children are worrying about him, instead of vice versa, and Izzie reassures him they're fine and are comforting each other. The man requests that she stay on for his surgery, so Erica reassigns Cristina to Miranda, over her protests.
Erica asks Mark to help her with the infected chest surgery and when he makes "jokes and sleazy come-ons," she says she'll ask the second-best plastic surgeon instead. He apologizes and says he'll help. During the surgery, she admires his technique and he talks about his mentor who taught it to him, saying how shook up he was when the man died. Erica says she's not interested in hearing about his "wounded soul."
Miranda requested Cristina to work on the racist paramedic because she's not black -- or white. Miranda reminds the patient that he might not live long with possible internal injuries and he reluctantly lets Cristina examine him. When she pulls up the man's shirt, he has a giant swastika tattoo on his stomach. Cristina asks Miranda if she can be let off the case to go back to cardio, pointing out that her stepfather's parents died in a concentration camp, so she's not thrilled about working on the guy either. Miranda tells her that the two of them will "rise above" and treat the man, regardless of his objections. He needs surgery on his liver and demands that a white doctor be present, as he's afraid they'll kill him on the operating table, so she pulls George in. Miranda misses lunch with her husband to do the operation.
The driver of the ambulance has a tumor that caused her seizure. Derek is going to do a minimally invasive brain operation with a computerized probe to examine her brain, but once inside, the computer goes dead and he can't see what he's doing, meaning he can neither remove the probe nor continue. His only option is to demand a technician come out immediately to fix the system.
Mark shows the residents a patient, Nick, who is in danger of bleeding out: a surgery to remove a tumor on his neck has left his carotid artery exposed. Nick is bored, so he chats up Lexie. He tells her his girlfriend left him because of the tumor and that she was a nice girl disguised as a vapid narcissist who turned out to be just a vapid narcissist. He asks if Lexie's seeing anyone and she says she is, a nice guy who can seem like a jerk.
Ava unexpectedly shows up to see Alex and he tells her he's about to scrub in on a surgery he can't miss. She asks him to sneak her in to view it and he puts her in some scrubs and lets her sit in the gallery. As luck would have it, Lexie sits down next to her and Ava says she's there to watch her boyfriend operate -- pointing right at Alex. Ava asks if she knows him and Lexie says, "No, I don't know him at all."
Lexie, still upset over Alex, goes to check on Nick and he asks her what's wrong. She tells him her "nice guy" boyfriend turned out to be a jerk after all. He suggests she date him to make Alex jealous and as they're laughing over his joke, his artery blows and sprays blood all over a shocked Lexie.