(Olivia enters the locker room where George is sitting) 

George: Um, about before... 

Olivia: George, I want you to understand, when we started dating, I was already kind of seeing someone.  I didn't know how much I'd like you, and when I realized, I broke it off with the other guy ... 

George: Other guy? Who's the other guy? 

(Olivia looks up and George turns around to see Alex standing there) 

George: You and Alex? You and Alex?! You gave me syphilis?! 

Olivia, Izzie, Cristina, and Meredith: George! George! George! George, back off! 

Meredith: Alex! 

Cristina: George! 

Izzie: Back off, Alex.