Jackson also gained some focus from their interlude but for him that means he finally starts kicking some medical ass; when he gives on answer to a question, the examiner seems happy and satisfied with it despite the fact that they are to reveal nothing.
Callie has Nick on the operating table and is digging around looking at something in the vicinity of his spine. Bailey is assisting, while Arizona hovers in the background and tells them all about how Nick gives cameras to orphans and saves puppies and helps little old ladies cross the street. Callie tells her that she's not going to kill her friend, and Arizona tries really badly to act cool and like that's not what she was worried about at all. Callie seems to find something of interest while she pokes around and then calls to Arizona that she forgot to bring snack for Sofia's class today, and she's so very sorry but Arizona needs to go get some. Arizona isn't happy about it but there's nothing much to be done and she goes. Once they are alone, Bailey admits she knows that Callie didn't actually forget snack and Callie agrees and shows her that there are mets in Nick's blood vessels which means they are going to be everywhere.
As Derek works on screwing a plate to Charlie's skull, he explains to Lexie something about a muscle that is going to atrophy from lack of use. He pointedly tells her it's too late for this muscle, because it missed its chance to attach. Mark is thoroughly confused but Derek just tells him that this is a teachable moment and he should stay out of it. Derek goes on about the poor, unattached, withered, fat-hugged muscle and Lexie finally seems to understand that this is all advice in code. Honestly, this metaphor is way better than "the test is a mirror." Unfortunately, Mark does exactly what Bailey predicted and seemed to use this metaphor for his real life -- he tells Derek he got the message loud and clear, and thanks him. Everyone is confused and a little bit surprised including Derek, since he has no idea how Mark could think that was advice for him.
As Callie, Bailey and Teddy look at some scans, Arizona comes in and tells Callie about how they totally didn't have snack today but stops chatting when she sees everyone's sad faces. Callie tells her gently that they did a PET scan and there are mets all throughout Nick's body, including his heart. Ah, that explains why Teddy is there. Bailey tells her quietly that there's very little they can do from here on out. Arizona is horrified and finally just leaves without saying a word.