He's only been getting caught, arrested, prosecuted and convicted of harming innocent civilians for 22 years. Had he continued in that same pattern, he likely would have been given further reprieve after reprieve to harm more of us, BUT now that he has attempted to harm the "only ones" (who are good enough to bear arms outside the home for self-defense, aka "cops") he may actually be put into a higher security incarceration facility where even the incompetent Hawaii government might keep him from escaping again and victimizing more of us.
Also, given that he had a (defective) shotgun that only fired one round and thus wasn't able to succeed in shooting the cops, it's clear that Hawaii's commonsense gun safety regulations need to be modified to retrofit all guns to be single shot only, include all long guns in the waiting period requirement, and increase the waiting period to a more reasonable amount of time, say, 365 days, so a truly thorough background check can be done. Then Hawaii will be crime-free for sure. And if not, just a few more restrictions on firearms will fix it.