Why doesn't rape grant a license to kill in self-defense?

Presumably, during an attempted rape, the victim is allowed to defend her(/his)self including using lethal force. At some point after the attack, this legal allowance seems to go away, but why? Surely once a person is a known rapist, that person can be reasonably expected to remain a threat.

So at some point during an attack and until the attacker stops attacking, the victim is allowed to try to kill the attacker. If they succeed, good for them, but if the victim is defeated, it would be considered murder afterwards?

What if attempted rape gave a license to the victim to attempt to kill the assailant even well after the attack, including the right to deputize others to do it?

(This question is inspired by this other question .)