I think she wants her body back, so that she can live the life the current Raeliana is living. Since the reason she went into Beatrices body was bc she was suppose to die
If one doesn't kill the other both will die. Both their souls are slowly dying because there's some imbalance due to the body swap. Can't recall the exact explanation why but I guess its either because fate is owed one soul (Rael was supposed to die but didn't) or maybe because their souls can't settle in a new body if the old one is still walking around.
Bea did cause all of this in the first place so it's her own fault, but there are no other options. The only way for her to survive is to kill Raeliana and vice versa.
I still don't understand what the blonde bitch wants really? Does she want to live and take the original Beatrice's life for hers? Or Noah? Idek anymore. What do u want really girl? You can't always have the best of everyhing. Especially with that attitude.