Callie and Arizona are packing for Africa, and Arizona is annoying Callie by giving Sloan her waffle iron and French press.
Meredith tells Derek about a grant that could get their research going. Cristina walks by and Derek asks Meredith if things are frosty between her and Cristina because the chief gave Hunt the $1 million grant and not Derek.
Teddy hands Cristina the files for Mr. Henley, the lung transplant patient from two weeks ago. Cristina seems nervous and Hunt tries to reassure her.
Hunt starts his trauma training by yelling at all the doctors to rush out to the "scene" of a bus accident outside the hospital. Each of them will be responsible for nine patients and getting them on the evac helicopter.
Sloan and Lexie get a patient who is looking to get her butt. Cristina is treating an older man who is nervous about getting new lungs, but says he's possibly more nervous about seeing his daughter, who soon walks into the room, calling him "Roy." After a brief reintroduction, Roy stops breathing. The nurses come in to assist, but Cristina freezes.
Cristina explains to Mr. Henley's daughter that her father's heart is failing, so there's a possibility he'll need a new heart.
Arizona has treats from her kids in a box while Callie is packing medical supplies. The chief comes up and says it's a shame that they're both going, and he tells Callie he had "big plans" for her.
Cristina goes to Dr. McQueen for some advice on what to do with Mr. Henley. He asks her a couple of questions and realizes she knows exactly what she's supposed to do. He sends Cristina on her way and says he'll be there when he can.
Bailey goes into pathology to assist with Mary's autopsy. She's a little stunned at the pathologist's matter-of-fact approach to the situation.
The doctors in Hunt's training are working on their massive number of dummies strewn about when Cristina walks out and sees the scene. She seems taken aback a little, but tells Hunt she's fine and needed some air. She gets a page and has to go back to Mr. Henley. Hunt tells her she "can do this." Hunt calls Meredith over and says she's "certified," and asks her to go in an help Cristina.
Meredith goes in to help Cristina, who is inserting an intra-aortic balloon pump. Meredith starts to get ready to help, but Cristina asks her to go give Mr. Henley's daughter an update. All this is after Cristina telling Meredith she doesn't need a babysitter.
Outside, April gives Hunt a status report on her dummy patients. He tells her one of them died because it developed a bleed she didn't notice because she wasn't paying attention. It starts to rain.
Dr. Stanley, the pathologist, is on her bluetooth making dinner reservations while she and Bailey are cutting into Mary. Bailey tries to point out some blood clots that could indicate a pulmonary embolism, but Dr. Stanley blows her off.
Callie is wondering what the chief meant by "big plans," trying to mock him but it's clear she doesn't mean it.
Outside, Hunt chides Alex for using a plastic bag to keep himself dry rather than using it on his "patient." April gets upset and rips the bag off Alex to keep her patient dry.
Meredith goes and talks to Roy's daughter, who is feeling guilty about calling her dad "Roy." It was something she decided to do on the way to the hospital, and now she's needing for that not to be the last thing he hears from her. Meredith goes back to tell Cristina that the daughter needs to hear from her directly, but Cristina says she's "kind of busy" with Roy. She reveals his leg. It's blue. This is bad.
Meredith calls Teddy, who says there's a chance that once the transplanted lungs are in place the heart damage will reverse.
Bailey argues with Dr. Stanley, who wants to take a break for lunch, about the urgency of finishing the autopsy before the organs begin to decompose.
Lexie comes back from getting cupcakes that Sloan had asked her to pick up for Callie and Arizona's sendoff. She then goes into a rant about how their butt enhancement patient shouldn't be making changes to her body to please a man. "Next thing you know, she's giving up her friends, she's moving in with him before she's even ready, and if she's not careful, she'll find herself a 26-year-old stepmother to the pregnant daughter she didn't even know he had. And then she's single, dying her hair a new color, and, you know what, it's really hard to manage your roots when you've been committed to the psych ward." (Lexie isn't talking about the patient anymore, apparently).
Bailey goes to sulk and finds Derek. She tells him about how food seems to be more important to Dr. Stanley than getting the autopsy correct. Derek says he's sulking because he's trying to write his grant proposal for the Alzheimer's research he wants to do. He says the more he learns the more depressing it gets -- especially considering the early-onset form that Ellis Grey had.
Lexie goes to talk to Sloan's patient, who tells her that she has "an amazing ass." She says she envies an ass like that, and tells Lexie she's getting "a big, juicy, easy-to-grab-onto ass" and she's doing it just for herself.
Alex mocks Hunt's training and says he's just trying to break everyone. Avery agrees, and gets up and leaves despite Hunt trying to tell him to stay. April jumps to work on Avery's "patient."
Bailey and Stanley have a run-in after Stanley gets annoyed that Bailey is trying to tell her how to do her job. Stanley goes on a brief tirade about how she didn't fail medical school and that she actually knows what she's doing. Then she says the autopsy was inconclusive, and that it upsets her as much as it upsets Bailey.
Roy is stable and Cristina doesn't want to go talk to his daughter. She says that his daughter just wants to make sure that Cristina knows that she's afraid. Cristina says she can't hear that because she's scared all the time. Meredith offers to help and Cristina snaps at her, saying, "You can't help me."
Callie is disappointed that the going-away for her and Arizona is sparsely attended (it's just Sloan, Lexie and the chief) and consists of a dozen grocery-store cupcakes. The chief says everyone is busy because they're down a couple of attendings. He again alludes to his big plans for Callie. She asks what they were, but he says he doesn't want to give away his big ideas. Arizona leaves to do some more packing. Callie says she doesn't want to go home. Sloan invites her to watch him and Lexie give a lady a really big ass. She accepts.
Outside, April flips out after Hunt tries to tell her that her last two "patients" are about to die. She throws them into the nearby ambulance, which he claims isn't "in play," and drives them around the corner to the ER doors. She unloads them and Alex tells Hunt to tell her that her team has won and that she's actually saved the last two patients. Hunt relents and April is pumped.
Derek is still struggling with his grant proposal and Bailey comes in and asks him to go over Dr. Stanley's head on taking one more step with the autopsy. He says he can't and she has to let it go. She says she can't go tell Mary's husband that she doesn't know why his wife died. And she reminds Derek that he shouldn't talk about letting things go, because he can't stop thinking about the possibility that Meredith getting Alzheimer's long enough to write his "damn essay."
Meredith finds Cristina on the roof waiting for Teddy to arrive with Roy's lungs. Cristina asks Meredith why she's OK. Cristina then begins yelling at Meredith for having put her in the position to save Derek. She says that if it were anyone else on the table she could have walked away, "and then I wouldn't be here." Teddy arrives and asks for an update on Roy, and the conversation is over.
Sloan and Callie sit and talk, and he laments the fact that she's leaving. He goes into a little lesson about how he sees boob job patients come back a year or two later regretting the choice they've made because they did it for a boyfriend. He says he isn't worried about the butt enhancement patient because she made the choice for herself. He finally tells Callie that she sounds "an awful lot like someone who's getting double D's just because her girlfriend likes a big rack. Big 'big rack' I mean Africa."
Callie says she loves Arizona, and Sloan says she needs to figure out how to love Africa, too. They hug.
Hunt tracks down Avery, who says he doesn't need "lessons on how unfair trauma is," because he lost two friends during the shooting. Hunt says he lost dozens of friends in the field and he's never used them as an excuse to quit being a doctor. He says he must go back outside and finish.
Teddy and McQueen finish up Roy's transplant and his heart begins to work. Teddy praises her for a job well done.
At the airport, Arizona stops and tells Callie she's ruining Africa for her after having won a hugely prestigious grant. She says she doesn't want to go to Africa ... with Callie. She tells Callie to "take care" and walks toward her plane. Callie pleads with her, saying they can work it out. Arizona shakes her head and tells Callie to "stay here and be happy, and I'll go there and be happy."
Callie tells Arizona that if she gets on the plane and goes without her, "we are over." Arizona says they're in the middle of the airport screaming at each other, meaning they're "already over."
The chief finds Cristina to give her a "well done" after hearing about her work on Roy. Cristina asks him if he has a moment to talk, but we don't see the conversation.
At the bar, Alex and April have a beer and he laughs about her outburst with Hunt. She laughs along and flashes a bit of a flirtatious face. Lexie catches Sloan checking out her ass. He says it's "not the first time -- won't be the last time." She tells him, "No," then walks away, smiling as she knows he's watching.
At home, Derek tells Meredith he had a terrible day because he was trying to write the grant proposal and couldn't because he was distracting her. He says he knows she wants to be part of the trial, but she can't be anywhere near it. Meredith tells him that Cristina hates her and blames her.
Outside, Hunt is urging Avery along. Cristina walks out and Hunt excitedly tells her about how great April was. He asks how her day was, and she says she quit.
"You were right," Cristina says. "I can do it. I can still be a surgeon, I just don't want to anymore."
Cristina looks up and takes a deep breath.