A person is only allowed to use deadly force in response to deadly force. If a woman reasonably believes that her life is in danger from being raped, then she may use deadly force. I think it would be tough to sell that one - in the usual rape case, a woman's life is not endangered from being raped unless there is something else going on in addition to the rape.
A person cannot use deadly force to prevent just any crime, rape included. You'd have better luck using deadly force when you were the victim of an armed robbery. There, an argument could be made for a reasonable belief that your life was in danger.