Jackson is studying a YouTube video of a nerve graft when Mark walks in, and he shuts the monitor off just in time as Mark asks him why Alex is suddenly helping out with this surgery they have been prepping for weeks. Because Jackson was determined to be oblivious about the state of his relationship and then decided today to cut off his nose to spite his face, Mark. Mark is just heartbroken that their team has been broken up. "The Plastics Posse? Kicking surgical ass and taking names?" Jackson finds this nickname appalling and Mark admits he was just testing out the sound of it. Jackson lies that he has a paper due and that he can't possibly be late turning it in since it's now fifth year and all. Mark seems to accept the answer and leaves, dejected, while Jackson, who has spent years and years in medical school, goes back to watching a procedure he now won't be doing because of a girl he just realized is still in love with his mentor even though it's been strikingly obvious the entire time.
Callie goes and finds her wife, who is hanging out with Polly, looking intently at the children's art on the wall in the hospital. Callie doesn't realize she's with Polly and immediately launches into an apology that includes comments on their marriage and sexuality. Arizona turns to Polly and asks for a second, so the girl takes off to look at their nuclear protein machines, like you do. Callie's embarrassed to have put her foot in her mouth yet again. But Arizona, to Callie's surprise, totally understands why it is that she didn't tell Mrs. O'Malley about what's going on. She points out that while coming out to one's friends and family is a crucial step, coming out to one's dead husband's ultra-Catholic mother isn't necessarily on the "must" list, at least for them personally. Callie is relieved and thanks her, and Arizona runs off to find her genius would-be fellow.
At lunch, Alex finds Jackson in the cafeteria and gripes that Mark won't shut up about him and the Plastics Posse. Jackson is embarrassed about the name when really, he should probably be making a mental note about how much Mark wants to teach him. Alex gripes that he wishes Arizona talked about him like that. Lexie walks up to them with a really thick book in hand and her finger in the middle, as if she managed to catch up on at least 200 pages in the hour or two since she last saw her patient. She's already obsessed with Kate's waffling between the 1890s Paris pickpocket who she can't trust and the hot American WWII soldier. She then dashes off, sending Jackson an air kiss as she goes. When Alex turns and sees Arizona laughing with Polly, the two disgruntled docs decide to go eat lunch somewhere else.