Most people act all tough but in really they wouldn't shoot. If you wanna test if you'd actually do it like you say it's simple. Go to a window and look at the first person you see that you don't know. Stare at them and then think "could I shoot them". Play it out in your mind. You're holding a gun and about to shoot them. You'll see most of you will say no. It's easy to shoot a faceless respawning game avatar. When you can look a stranger in the face and think "Yeah, I'd do it." I'll believe you.