This is why PROPER TRAINING is ESSENTIAL!.  Hawaii law regarding "lethal use of force" isn't very complicated.  Actually pretty simple. Only 5 reasons why it would be allowed.

1) Fear of Death
2) Fear of Serious Bodily Injury
5) Fear of Kidnapping
4) Fear of Rape
5) Fear of Forcible Sodomy

Don't believe me, then check out the Hawaii Revised Statutes.

 §703-304  Use of force in self-protection.

Properly trained, law abiding citizens shouldn't have an issue following the law.