Owen reminds the teams that the surgery on the twins will last at least 18 hours, and each doctor is to get there at least 30 minutes before their procedure. With that, Arizona and Jackson begin the final practice run. She's really jumpy and keeps cutting off everything Jackson says and basically takes over every single step whether it is supposed to be hers or not. Richard and Alex are watching what's going on and Richard, who came in on his day off just to see this, mentions casually how wound up she is. Alex is helping out with the "flip" and he says he's ready, but as they watch Arizona's nitpicking Richard points out that she'll destroy everyone else's confidence that way. He then reminds Alex that if the flip goes wrong she will blame him and it will look really bad on his record, right before the boards and all. On cue, Alex is then up for the practice flip and the doubtful glance he shoots at Richard shows that Richard has done a good job gnawing away at Alex's confidence.
Out in the waiting area, Lexie is explaining to the extremely young parents why the flip is so important -- the babies will have open incisions that need to be kept sterile, they need to stay intubated, and the docs need to keep all of the various wires that are attached to them from getting tangled. Seeing that they don't really understand what most of that means (they obviously don't watch medical procedural shows every week) she compares it to changing a car battery while speeding down the freeway. She immediately realizes this is a rather insensitive metaphor since she is talking about their actual children, but the dad points out that this is the first thing he's really understood all day. The young mom, Gretchen, is extremely worried but Lexie assures them that the doctors have been practicing for weeks and have it down pat.
Back in the OR, though, the practiced choreography has dissolved into a shouting match between Arizona and Alex as they hopelessly tangle up the baby dolls and blame each other for Brandi and Andi, the twins, now suffering all sorts of damage from the botched flip. Owen just calls them back and has the other doctors move on with the next step of the surgery. Meredith leans over and points out unnecessarily to Alex that that was a disaster, but he argues that he's got this down and all would be fine if Arizona would just trust him. Bailey then comes in and calls Meredith away.
Once in the hall, Bailey admits that she's going to tell Meredith something about her personal life, and Meredith almost falls to the floor in her utter shock. But let it be noted that there's also an undercurrent of extreme excitement in her voice that the Miranda Bailey Emotional Vault is about to open. Bailey is quick to tell her how much she loathes knowing so much about Mere's personal life as well as the idea that Mere will now know anything about her, but she sees no other choice. She then admits to Meredith that she and Ben are involved. Mere points out that everyone knows this, but Bailey yells at her to act surprised, so Mere does so accordingly. Bailey explains that during surgery he is going to want to discuss personal business and that Bailey doesn't want to, so she needs Meredith to ask a lot of questions and play dumb in order to change the subject. Mere is rather put out to have been pulled out of a once-in-a-lifetime surgery to act as a buffer, but Bailey doesn't care.