Teddy thinks that Mrs. B. has an air leak in her chest tube and has Meredith sign them up for an OR just in case it doesn't get solved. In the next bed, Emile is clearly worried.
Lexie and Avery run into the OR clutching Frankie's arm and shout that they saved it and it's ready, but Hunt rains on their two-man parade when he announces that they have to amputate as there's too much wrong with the stump. Mark adds that they could push antibiotics and give the stump a few days but then the arm would be dead -- clearly this is for the viewers because the doctors would know that already without it being spelled out. Lexie is really upset and says to Avery that they could attach the arm to a healthy zone while the stump healed, so he challenges her to tell someone who matters, calling her "Mouse." He then shoves her forward and she blurts out her idea to Mark and Hunt, who are rather intrigued at the idea of transplanting the arm somewhere that it could hang out while the stump healed. It's something that hasn't been done before and Hunt tells Lexie that he would lose a lot of range of motion in his elbow but she argues that she promised they would do all they could and that he deserves extreme measures. The men are swayed by her passion, and talk it over a little more given that it's something neither of them has ever done before. Lexie adds that after today they won't have the ability to choose if they want to try, and Avery tries to hide his smile as he watches her plead. Hunt tells them to both scrub in, and Mark gives her an appraising look before he heads out. Avery then tells her that she was definitely not mousy just then.
Derek seeks out his Post-It wife and mentions the brunch, which she tells him she knew about from a resident currently rifling through her closet. Derek apologizes for April's being overeager, and Mere then tells him that she has a surgery she can't just give up. Derek immediately says that he doesn't want her to, but Mere is obviously having a bit of an internal struggle because she goes on justifying her decision -- her patient is someone's wife too, and Mere is her doctor and needs to be there. She's stalling and tripping over her own words and when Derek smiles at her and tells her it's okay, she's clearly still unsure about the whole thing. Once she leaves he seems a bit bummed, but not surprised. I'm kind of curious why this breakfast didn't come up before, given that trustee brunches are generally not thrown together on a mere 12 hours notice, but man does it work nicely with the day's other stories about adapting.