it is avoidable through the private citizens being armed.  If this istuation had unfolded in front of me, you can rest assured that I would not have hesitated to shoot and kill the person doing this.  If more private citizens are armed, the chances of this kind of thing happening decrease...just look at the statsitics...in every state that has enacted concealed carry laws, the violent crime rate has dropped significantly.  Criminals think twice when they know their victims might shoot back.  Later.

Eric