In the O'Malley room, Izzie asks them why they chose to change surgeons. She's really respectful about it, just curious and maybe confused. They both tell her that George made the decision, and muse that maybe he fell out with Burke. Mrs. O'Malley then excitedly wonders if he's going out with Dr. Hahn. I have officially never seen a mother so intent that her son get laid. Mr. O'Malley reiterates that Callie is in love with George, which leads Mrs. O to ask why she would break up with him if she loved him. She asks Izzie in a conspiratorial girl-talk way, which is maybe what leads to the horror that comes next. Izzie asks what she knows, and Mrs. O'Malley assures her that it's everything, because she is his mom. Taking this at face value, Izzie launches into Callie being "out there" and how much she's naked. Both the 'rents are understandably shocked, which Izzie notices, and softens. She points out that "George seemed to really like her, and he kind of needed her." I'm proud of her for saying that, even if admitting those things came in the middle of this car wreck of a conversation. Because he especially needed her after the "Meredith thing... " which of course they also knew nothing about. The one great moment in all of this embarrassment is how proud Mr. O'Malley is that his sons are studs. The least Izzie can do to make things right is assure them that there's nothing going on with George and Dr. Hahn, and so they again ask why she'd be doing the surgery if she's not better than Burke. Izzie concedes that she's good, but Burke is the best, so they put Izzie on the case to find out why he's not going to be their surgeon.
She goes into the locker room, where she finds Meredith on a Blackberry. At that moment Callie comes in and, with a sneer, literally begins rolling up her sleeves, says she wants to talk about "panties," and declares that she's kicking Meredith's ass as she picks her up and throws her against a locker. She's hollering about how she was a good friend and discreet and that she can't believe Mer did "this," as Mer screams back, wondering what "this" is. Izzie is screaming over both of them, telling Callie to "use her words." Her words come in the form of the secret of the panties, and the "adulterous McSex" that she saw, which doesn't explain much of anything, and Izzie has to actually throw herself in between the two, screaming, "I'm sorry but she's very little and you're hurting her!" Best. Line. Ever. It's funny 'cause it's true. Callie finally yells that the McSteamy sex wasn't Meredith's story to spread, and Izzie sighs, not believing that was the big deal. Unfortunately this earns her little friend another beating, since now Callie thinks Mer told Izzie as well. Meredith's lungs are stronger than her bones and she's finally able to yell back at Callie that all she'd known was that Callie slept with somebody, and that George was the one who told her it was Mark. Callie is stunned into silence and wonders who told George. Izzie suggests, "Maybe perhaps the guy you slept with?" (Although it was Alex, the point remains that the girls weren't the gossipy ones this time.) They all breathe, and finally Callie... desperately says that she didn't betray George and that they were broken up at the time. You thought I was going to say "apologizes," did you? Silly rabbit, apologies are for suckers, at least in this hospital. Or so we're generally led to believe. Meredith orders her to go tell George just that, and when she leaves the two girls dissolve into sort of manic giggles as Izzie notes, "Dude, she went all cage-fighter on you!" Second best. Line. Ever.