I know that dick-pain can be pretty intense, but I imagine someone who is prepared to brutally rape a woman is going to have enough adrenaline flowing through them that these teeth aren't going to leave them writhing on the ground while the victim flees.
If someone can take some fingernails clawing into them and gouging them while they rape away, I imagine they will be able to kill a woman with this thing mutilating their members.
It's seems like a great device at first, but like several people ITT, I think it will just lead to women getting killed and rapists figuring out how to remove these on their own.