That was a freaking fantastic episode. But I want to know how she went from calling him a liar and wishing to go home so fervently, to being gung ho about infiltrating and destroying the Losties.

I was wondering about that as well....
She REALLY did want to get off the Island, and she wasn't a bad person in the first place. I wonder what made her go along with the plan.

I wonder if Sun is going to die, since she is pregnant....