You already answered your own question...she's playing the game perfectly. She is actually one of the only characters in this episode in a win-win situation.
For now....she is still safe with the Lannisters. As long as Jamie is still a prisoner (He isn't, but everyone thinks he is) Joffrey/Cersei can't really fukk with her...they still need her as leverage. Besides, even if Joffrey is a punk bytch, she IS his fiance. The Lannister win doesn't change her situation much.
If Stannis had won...as she herself said, he probably wasn't going to fukk with her. Stannis doesn't want it with young Wolf Robb, and he probably doesn't even really give a fukk about being a "king". She probably would have been returned to Winterfell, assuming that Robb respected the iron throne and didn't try to keep up with this king of the North stuff. Regardless, I doubt she would have been raped and killed...Stannis too smart for that.
Leave with Hound.....this crazy ass nicca? Who knows what he would do to her, and if she was CAUGHT trying to leave, this might have forced the Lannisters to punish her, regardless of what it meant for Jamie.