I have this theory that she's still alive. Before she died she said she could help him/her. What if he/she was about to kill her then stopped and agreed to it? Her body was found dead, but it could've been an act. My theory does have a lot of plot holes like why would the Red Devil trust her? Wouldn't he/she think she was going to betray him/her and tell people the identity? Or how did she stay in the tub all lifeless without moving at all(Although Boone did do this so we know it could happen). But It could be possible since we didn't actually see her die, we'll just have to see if the body just disappears or if they bury it.