You are standing in a shopping mall, when you hear a 'clunk!'
You look down.
There is an automatic pistol on the floor, beside you.
You pick it up.
It is real, it is loaded, and the safety is off.
At this point, the guy who dropped the gun takes another one from a bag which he is carrying. Standing in the middle of the mall, he proceeds to fire at shoppers. There is a large, thick concrete wall behind him. You have a clear shot.
Do you use the gun?
For those of you who might be tempted to shoot him in the arm or leg, first consider how good your aim really is.