Cristina and Teddy are discussing the first steps of this stem cell experiment: Cristina will take hearts from animal cadavers and use a solvent that will drain them of all of their cardiac cells, which Teddy explains is like stripping a building down the studs. She then goes on and explains dreamily that they are scrubbing away the heart cells, wiping them clean until they are blank and then injecting them with stem cells so that they will live again. Cristina's face is blank as all of this talk of erasing and rebuilding hearts is hitting a little too close to home. Alex comes in, having traded with April so that he is working with Teddy. Almost immediately his fancy new pager beeps as Morgan tries to track him down. Teddy gets her own page and the two go down to the ER, leaving Cristina alone and staring sadly at the table until she picks up a football-sized animal carcass and gets to harvesting hearts.
Derek and Lexie are looking at scans and to her surprise, he gives her instructions for how to clip the aneurysm they are about to face. She is shocked, asking if he's sure and admitting that she really screwed up on her last surgery. He agrees, but tells her that she is a student and this is how she will learn. Wow, that sounds strangely levelheaded coming from Derek Shepherd. He asks if she has any more questions and is very surprised when she asks if he's going to tell Mark to move in with Julia. He almost physically recoils as she babbles that Julia works on eyeballs, which is boring, and has thin hair which can be a sign of early menopause. Phew, if that's the case, I'm not going through that for another 20 years at least. Once he can get a word in edgewise Derek informs her that they don't talk about this kind of thing, and he leaves.
Poor April is in a rather unenviable position with Morgan, who is completely worked up that someone other than Alex is there. It's worse because something is going wrong with Tommy, and Morgan is yelling at April, telling her she's not doing things the way Alex does. Finally, April yells for the nurse to page Arizona but Morgan speaks up and tells the woman to page Alex, instead. It's pleasantly shocking when April puts on her respect-getting lower voice and hollers at the nurse in no uncertain terms that she's to page Arizona; even Morgan stops yelling for a moment.