Callie has nearly finished fixing Mom's knee when Mark walks in to the OR, and upon seeing Alex bellows at him to get out. Callie thinks he's out of line but Alex is more comfortable just leaving on account of Mark's "serial killer eyes," and once he's gone Callie tells Mark in no uncertain terms that enough is enough. Mark just thinks it's funny that he scared Alex, but his face slips just a bit when he realizes that Callie is truly upset with him and she calls him sad and pathetic. She warns him that he has a choice now, to make Sloan leaving the best or worst thing that ever happened to him. His choices are to grow up and find a woman and have a baby of his own, or he can be the asshole doctor who abuses residents and sleeps his way through the entire staff. What she's describing is actually pretty much who he was before Lexie, and look how well that worked out -- the nurses all got together and ganged up on him for being such a manwhore. Callie orders him to pick one, and he just stares back at her, in shock that she's so serious.
Alex has joined the other residents and they all are hounding Jackson to meet his grandfather, but he's totally against it. Alex tries to bribe him with possible friendship, while Charles flashes him some hospital gang signs as he asks what happened to Mercy West forever? Jackson points out that this wasn't a thing, and though Charles is right now just trying to score an invite, I'm pretty sure for him it was a thing. He shoos them all out of the locker room and then plops down with a dramatic sigh while Meredith does research at a nearby table. She glances up at him and it's the opening he was looking for to complain to the only person who would understand about how much he hates it when people know they are related because they treat him differently. He grudgingly admits that having the name has also helped him out but tells her that Harper is not an easy man even though he's brilliant. Mere just gives him a very understanding smile, and then he gets a 9-1-1 page and they both dash upstairs to Harper's room.