Okay. Back to the matter at hand, which is to strike to cripple. (What are you thinking of anyway? Cutting off their dick?)
You have a point.
Is there a way to tell whether a guy raping you intends to kill you afterwards?
No theres no way to tell.
If you want to do serious damage, kick down on his kneecap with the side of your shoe hard.
*Bring the heel of your hand up onto the bottom of his nose with all the strength you have. (chance of death)
*Always go for the balls, dry to damage them permanently.
*Breaking the fingers is usually effective.
*Gouge out the eyes.
*If you can get ahold of a blunt object, hitting them in the back of the neck really hard has a chance of paralyzing them for life.
-I'd give you and in depth step by step lesson with many more of these, but i'd have to do that in person.