Once upon a time, when this country was sane, our thinking was that those who abrogate the social contract (e.g., commit major crimes) had given up the right to total protection from that social contract. So the notion of suing a homeowner -- of the law allowing you compensation -- because you broke your leg while burglarizing his home would have been unthinkable, even laughable.
Unfortunately our Modern State will probably seek to use this to restrict the rights of the law-abiding instead.
I'd heard that one quick-thinking student set off the fire alarm in order to get people to evacuate -- i.e., to get away from the knife-wielder. What do you want to bet the young hero will be suspended (or expelled!) for setting off a fire alarm when there was no fire, or for not obeying the school's rigid lockdown/"shelter in place" procedures?