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 next 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.
Poor Ben, he comes home, Bailey tells him she's disappointed in him, and then she seems to be spiraling into some sort of emotional trauma/PTSD/affliction yet to be explained. He wakes up in the middle of the night to find her searching Tuck's room since she insists that there's a strange smell in there. Ben can't smell a thing and urges her to come back to bed but Bailey insists that Tuck has a habit of leaving food in the room when he goes to his dad's. When Ben mentions that it is a big day tomorrow Bailey comments somewhat snidely that he's going back to his old job, couldn't he do that in his sleep? Ben refuses to take the bait and just offers to help, but she declines, pointing out that he can't find something he himself can't smell anyway.
Mere's VO this week is about tumors, and how when doctors fight them it's not just a fight against one thing, but actually a war against a billion cells. Alex finds his teenage patient Will up in the middle of the night playing video games even though he has surgery the next day. He's not nervous, it's just that there is a crying baby next door and the prints of a happy monkey and frog (more suited to a 5-year-old than 15-year-old) are kind of creeping him out. Alex continues to be as awesome with kids as he is bad with adults and talks to him about the game before taking the controller to try his own hand at a particular level.
Mere has fallen asleep at the hospital and Stephanie wakes her to tell her excitedly that "it" is starting to take shape. The two go and stare into the bright glow of the 3D printer like proud mamas.
The other residents are all gathered around Richard's bed like a team of butlers, pouring him coffee (that is sitting next to the bud vase on his table) and listening to him tell stories about interesting cases he's had throughout his life. Steph runs in but Richard shushes her so that he can keep talking and as part of his story he explains the "two challenge rule": in aviation, if the co-pilot disagreed with the pilot as to how they were flying, and said something and the pilot ignored him, someone else could say something as well and if the pilot doesn't acknowledge them either, then he has to give up control. I think of this more as "common sense" and "the way the world usually works" rather than a rule, but maybe you need something more formal when doing complicated things such as flying planes or performing surgery. Steph finally begins tapping her foot and when Richard lets her speak she tells everyone that "it" is 30 minutes away, and they won't want to miss it since it's life-changing. Presumably she means the great reveal of whatever she and Mere are printing even though she doesn't say so specifically. As they file out, Smash invites Richard to come with them especially since he's supposed to be up and walking. Richard makes an excuse, however, and after Smash leaves the woman next door, CJ, starts hollering at him about how he's telling the same stories over and over. They bicker, and she notes that his hospital has crappy thin walls -- this means that no one even wants to be near an on-call room, like, ever, if that's the case. Even with their fighting, it seems like Richard is already fond of her.