Mere's 3D printer has arrived and there's a lot of excitement around what she will make first but everyone is underwhelmed when she pulls out… a fork. She then gets to work making a model of a liver, which just builds away throughout the day. She and Alex have a surgery to remove a bunch of tumors from a teenager with a super aggressive form of cancer. One of those tumors is smack in the middle of the kid's liver and once they are inside, Alex thinks it's too dangerous to try and take it out. But ever since Cristina told Mere she wasn't a great surgeon, Mere's been trying to prove that she's a genius at everything -- she's built up her confidence so much that she's gotten rather obnoxious and she's convinced she can do it. They have a showdown in the OR and Mere is livid when Stephanie backs up Alex's opinion and they shut her down.
Cristina and Smash are working together to treat a baby with a heart condition whose body is rejecting the implant they put in a little while earlier. Smash does some reading about the 3D printer and realizes that they could use it to make what they need, but Cristina flat-out refuses. He pulls a bunch of research from similar procedures in Japan and gets a special clearance from the FDA to do it, but Cristina still refuses because it's Mere's machine. Smash points out that it's actually the hospital's machine, and that instead of just making a model of an organ it could be making something to save a life that very day. After Mere storms out of the OR she goes to check on the status of her printing liver, and she's aghast to find the unfinished plastic liver on the table and Smash and Cristina using the printer for their own purposes.
When Derek went to witness the fork unveiling, he saw that the printer rep had a twitch in his eyelid. He tells Jackson he can fix it really easily and they accost the guy and convince him to let them operate. While they are working, Leah comes in to report to Jackson on their patients and he tells her that he'll take care of everything when he's out of the OR. When Derek stands up for Leah's ability Jackson says he knows she's good but he's just better so Derek starts insulting Jackson like Mark used to do to remind him that he's got to actually let the residents do things if they are going to learn.
Richard is supposed to be doing laps around the hospital floor but he'd rather hang out in bed and repeatedly tell stories about his glory days to the residents. The woman in the room door, CJ, has taken to teasing him about his stories and the two bicker like an old married couple. While she's doing her own laps, she suddenly collapses and with no one around, Richard finally gets out of bed and then shoos April away to handle CPR himself. He later admits that he feels amazing after finally doing something again, and he tells April that he lost himself for a while but now thinks he's finally found himself again.
April and Matthew are doing counseling in advance of their wedding and after one session, Matthew admits that he wants to have sex now so that their wedding night won't be awkward. April eventually agrees to this, but after hearing Richard's triumphant speech she realizes that she finally found herself since her indiscretion with Jackson and she doesn't want to lose that again. She also doesn't want Matthew to ever have that feeling, so they decide to wait after all.
A position is open in maternal fetal medicine so isn't it convenient that Owen's new flame happens to be a specialist in that field? She comes in and meets with Arizona, and then has her formal interview with Callie. Callie told Owen she'd grill Emma to find out not just if she'd be a good doctor, but also a good girlfriend for him. She does, and that includes asking personal questions that Emma points out aren't even legal, but of course Emma is awesome and likable and answers them anyway. In addition to finding out that she's a good person who wants kids one day, Callie learns that she was once married to a fellow doctor when they were at the Cleveland Clinic, but they got a divorce and she moved to Seattle because she couldn't handle working with him anymore. Later, she tells Owen that she can't take the job because she knows that if they break up, his friends will close ranks around him and shut her out, and she can't handle that (again).
Ben has come back to his old job as an anesthesiologist and he's working with Bailey and Princess on their surgery. Before it even begins, Bailey is out of sorts and freaks out when Owen moves the procedure to a different OR than the one she thought she'd be in, as well as when she finds out Ben switched so that he could work with her. During the surgery she has a number of moments of kind of spacing out and pulling on her fingers like she did back when she lost her surgical mojo last season, and she is also convinced that with each step they are not being careful or thorough enough -- to the point that she actually makes a mistake they have to patch up. Ben later tries to talk to her about it but she insists that everything is fine, though when he leaves her she starts pulling on her fingers so maniacally that I thought she might actually break one. It doesn't look like that happened, but something is obviously very wrong.