The same applies to self defense situations as well as hunting.
If a bullet reaches the vitals and doesn't incapacitate, it has failed as surely as one that doesn't reach the vitals and also fails to incapacitate.
Explain how a bullet that reaches the vitals leaving a quarter size hole through the heart will fail to incapacitate.
No doubt the person will eventually be stopped. But if you completely vaporized the heart, that person can remain conscious for up to 30 second...a LOT of death and destruction can be dealt in 30 seconds. Someone killed in that 30 seconds would say it was a failure to incapacitate.
