So I found it online. In case anyone else had this problem, I'm sharing here:
Grey's Anatomy 2/05/06 Episode: "It's the End of the World"
My doctor friends seem to be bothered by all the little things that aren't quite right about the show, but I don't care. It's good tv; and this is a really good one! This particular episode has girl on girl action (sort of), big time danger, sex, and a celebrity guest star. What more could you want?