One aspect of defending against a mass murderer that isn't touched on enough is the insanely ideological response from your public servants, especially the DA. You have to accept that you will likely have a second struggle after the shooting/hospital stay with the government.

If you don't, great. Go on with your life.

If you do wind up in jail awaiting trial for having a concealed weapon, assault with a deadly weapon, murder, etc. then you and your friends have to make a pact to get as much legal and financial assistance as possible. Everything from legal fees to media activism, to recall election procedures/impeachment against the DA, to commisary to paying the rent and debt notes while you're incarcerated. And you do the same for someone else.

And everyone in your group forms their own and everyone in those groups does likewise.