There is a difference with a Nut-job with a Gun and a Active shooter. Being LEO I carry everywhere I go (H.R. 218) Christmas, while at a service, I did go over what I would do if something happened.
Pryotex is TEC Tactical, A Licensed 07/SOT
Having a Black belt in TaeKwonDo. I learned the self defense laws of Denver, Colorado. A martial artist may NOT, without being able to to prove without any doubt that they believed they were in mortal danger, use deadly force. Period. If some idiot as I read at the beginning of this thread is outside a store waving a pistol, There is always a back door and a 911 cell phone. If and when that person points their gun at me, or begins shooting at someone else, then everything changes. Life is too precious to be a killer.