Criminal Minds, Season 2

Prentiss:
How could their friends not see anything?

Morgan:
It's like when the lion preys upon antelope.

Prentiss:
You lost me.

Morgan:
Well, that's because you, Emily Prentiss, have never been one of the antelope.

Prentiss:
Oh, scratch that. You totally lost me.

Morgan:
Okay, check this out. The antelope travel in packs; so the lion just sits and waits. Waits for just one of the antelope to break away from its herd. So when he's alone, vulnerable, and completely unprotected, that's when the lioness strikes, that's when she makes her move.

Prentiss:
Wait a minute, her move?

Morgan:
Prentiss, there's only one thing that's gonna make a straight man leave his friends on guys' night out, and it'll make him leave every time.