Addison is working away on Sloan, whose belly I swear is getting bigger with each scene this hour. Mark is in the OR watching over her shoulder as she works with Lexie assisting, and he's not happy when Addie realizes there's a complication. Sloan's uterine arteries are engorged but the only way to go cut the bands is between them. Addie opts to move forward but Mark is worried, and Addison has Lexie admit that the worst-case scenario is that one gets nicked and both mom and baby bleed out. Addison is sure she can do it but Mark is absolutely against the idea, and they argue back and forth. Addison's 95% chance that she can do it isn't enough for Mark, who orders her to end the surgery right now and after some back-and-forth, she does.
Derek marches into the OR as Bailey prepares for Tom's spleenectomy, and proceeds to have a haughty little tantrum when he realizes the Chief blew off the procedure. Bailey's not sure what his problem is as she was going to do the surgery in the first place, and Mere lamely reports that Richard said something about a budget meeting. Derek's amusement about Sheldon has worn off completely and he asks Bailey what's going on since he knows that was bullshit, and he's not going to accept "busy with the merger" as an excuse any longer. Meredith just looks at the floor, which is about as subtle as holding up a sign and dancing around singing, "I know what's going oooooon!" but Derek is fortunately more focused on Bailey, who tells him that it's not her job to get involved in Richard's personal life just like Derek shouldn't be involved in hers. Her tone is a little less sure than it usually is but she's still Bailey, after all, so Derek takes that as a final word (for now) and flounces out of the OR.
In the aftermath of Mark's outburst in the OR, he says he's sorry that she didn't like his judgment call. Addison very rightly reminds him that he put her on a plane immediately precisely because he wanted her judgment call, and cuts him off when he talks about the risk to point out that he acted like a father, which is why parents aren't allowed in the OR. He tries to deny it but clearly that's what happened, as he wouldn't have reacted like he did if he just had his surgeon hat on at the time. She toots her own horn a little saying that while most surgeons wouldn't want to take the risk and do the surgery she could handle it, and tells him that she can go in and try it again but that he will be kept in the waiting room. He tells her it's too risky, so she tells him positively that in that case they will monitor the baby's growth and see what happens. She leaves to go back to her actual job but before she goes, congratulates him on being an actual parent. She smirks while he heaves a pathetic sigh.