The next day, Mark sidles up to Derek and says he heard that Derek went rogue. Derek tells Mark that he's just doing a surgery he believes in, but I think there's a little bit of neuro god ego there too -- Isaac did a good job tapping into that to get the desired result. Mark, on the other hand, thinks he's just trying to piss off Richard, and Derek asks when Mark and Richard became besties. Seriously. Mark just says that he's the chief, and Derek mutters, "For now." I guess this means maybe they will have him gunning for the job sooner than later. Callie and Arizona come up and ask if he went rogue, having basically the same conversation. Derek points out that the computerized schedule says he is doing a craniotomy, so Richard won't find anything out. Arizona shuts him up since she is bad with secrets, but Callie compliments him on his badassness and then the ladies walk off. Lexie then walks up, completely offended that she wasn't asked to the skills lab to try her hand at the pen/George task, reminding Derek that she is his sister. Interestingly, she rubs it in repeatedly but never adding the "in-law" at the end of that. Mark reminds her that she's on his service, and Derek then says that if Mark will let her, he had a special job in mind. He needs someone to watch over him, remind him to take breaks, bend his legs, and drink water; basically, she would be his doctor. Lexie is thrilled, and Mark of course lets her off of his service, telling her, "Go get your rogue on."
An excited Lexie gets a drink from the vending machine, next to where Avery is getting a snack. Lexie makes small talk about being nervous to be in the OR that long, but Avery is just a completely cocky ass and asks why she's nervous since Derek didn't even let her compete. When Lexie tells him about her special role as Derek's doctor, he snickers and says that he thinks it sounds more like Lexie is his bitch. What is it with these Mercy West people and being someone's bitch? She just points out that Avery is going to need to take a bathroom break and when he does, she'll be there to take over. Avery just responds, ultra-confident, that he doesn't take breaks, and that he's lasted that long on a surgery before -- for starters, he knows to stop taking fluids beforehand. With that, he points to the drink Lexie is sipping and tells her to have fun playing nurse. Lexie's pissed, but then notices a supply rack nearby and looks at something with interest.
Cristina is on the phone with Mere, bitching about how Izzie might have had the right idea. As she paces, she looks through the window and sees Lexie holding something, so she says she'll call right back and runs in.