Callie and Arizona continue to argue about having a baby, but they're interrupted by Mark, who's banging down the door: He needs their help with Sloan's baby. When they get back to the apartment, Teddy's already delivered the baby safely.
Mark is ecstatic to be a grandfather and Sloan reconsiders giving up her child. "Maybe we should keep him," she says. Arizona thinks it's a terrible idea, since Sloan has no idea what she's doing, and she and Callie butt heads over the best thing to do. "This baby needs parents, not an 18-year-old child and a father she met five minutes ago." Mark tells her, "This is my grandson. I'm not just going to turn him over to some strangers when I might have a chance at a family." Sloan's freakout when left alone with the baby helps make Arizona's case. Callie tells Mark, "She's a baby herself." Mark and Sloan finally decide that giving the baby up is the best thing, but we can see how hard it is for Mark.
Callie suddenly has an insight into why Arizona doesn't want a child: She watched her parents' agony when her brother died! She tells Arizona, "I get it," but that their baby would be healthy. Arizona tells her she doesn't get it at all, "I'm not broken. My lack of wanting to have a baby is not some pathology that you can pat yourself on the back for having diagnosed. I like my life, the way that it is. I thought I liked it with you in it. I hope I'm not wrong."
The renowned cardio surgeon Tom Evans is at Seattle Grace for a consult, and possibly more. Derek had no idea that Teddy wanted to stay and thought he needed to fill the slot. Shaken to realize she might lose her job, she asks Derek to consider her for the position permanently. Cristina is thrilled to be assisting Evans all day, but when Teddy points out that he never even let her hold a scalpel, she realizes that she's much better off under Teddy. Teddy botches a surgery after Derek implies she's not qualified, and Owen comforts her when she starts to cry in the elevator and they seem on the verge of kissing when the elevator doors open.
Lexie is tired of Alex's brusque treatment, especially since they're still sleeping together. When she correctly diagnoses a tricky case, Miranda encourages her to take credit, instead of tipping off Alex, who doesn't even respect her. "Why do you want to hand your big save over to Karev? You are handing your power over to a boy because he's giving you sex."
Teddy's already in surgery when Lexie bursts in and tells her the patient has a highly contagious disease. Teddy reluctantly admits Lexie is right and stops the surgery before she's made a cut. Cristina begs Owen to talk to Derek on Teddy's behalf, but we're shocked when, unknown to Cristina, Owen tells Derek that Teddy "will be fine," if he doesn't hire her.
Meanwhile, Meredith is alarmed to hear April go on and on about how brilliant Derek is. She assures Meredith it's just professional, but Meredith is worried because Derek first got interested in her when she was an intern. Meredith's solution: She shows up at Derek's office, playacting that she's an eager young intern.
Derek gives Teddy the good news: She's got the job. Richard tells him he made the right call and Derek admits that he first offered it to Evans, who turned it down. Mark, who'd begged Derek to let her stay on, is thrilled she's staying.
Callie tells Arizona she's fine without a baby, but starts to cry. "Don't," Arizona says and kisses her.