I think prota just wants to be put out of his misery... Maybe he knows how strong he is and maybe he knows that this isn't normal and that he can't control himself so maybe he is just looking to die but each time he tries he gets sudden violent urges to the stimulus of pain causing him to kill which stop him from dying.
I think prota just wants to be put out of his misery... Maybe he knows how strong he is and maybe he knows that this isn't normal and that he can't control himself so maybe he is just looking to die but each time he tries he gets sudden violent urges to the stimulus of pain causing him to kill which stop him from dying.