Well yes. If I have a gun and the perp is on a spree near me, it is incumbent on me to stop him and this goes for any one else who is carrying for protection.
True.
When these murderers are cowards who destroy at night, it becomes impossible to stop them.
Sometimes they are also murderers who also want to die and hope for death by cop-shot.
We all try to do our best. THAT is all we can do.