When Arnold shot the gun, would he survive the shooting and how fast would the person who was shot go after being hit? Here's the math:
At the speed that Arnold would be flying back, he would have either died instantly after shooting or his arm would have been torn off. So Arnold would not be the one doing any saving in this film is real physics were applied.
The victim of this shooting would have flown back at a very fast speed so he would have instantly died and flown backwards.