She probably blacked out. I've seen her both ways; sometimes she's like a narcoleptic, out cold in mid sentence and pick it right back up when she wakes up, other times she will repeat the same sentence over and over because she can't remember she already said it.
Apparently it happened again with yet another guy, this time resulting in a pregnancy scare. He's a "good friend," though, so now I'm in trouble for questioning her choice of company, and definition of friend.
Some train wrecks are actually beneficial to watch, in that they remind me I'm pretty much incapable of doing anything quite that f'ing stupid.