This is exactly how they taught/trained us in the Academy. One may think they would not have a problem shooting someone and in fact, hit those blue man targets at the range with supreme accuracy, but I have seen so many training videos where it just didn't happen that way when the bullets started coming his or her way.
I am big on training as this was instilled in me at the Academy and it reminds me of a quote I will always remember by one of our instructors:
"The will to win compares little to the will to prepare to win"
The more training you undergo, hopefully stress induced type training, the better you will react in the way you were trained when the poop hits the fan.
This video is a sad one, but a perfect example of how one may react in this type of situation. Listen to the Deputy, his heart rate is def over 200. You can barley understand what he is saying, he orders the suspect back to the vehicle and once there, continues to order him back to the vehicle. Off camera, the Deputy strikes the suspect with his asp baton which only fuels the suspect more.
I can talk all day about this traffic stop but you can get the just of it by watching it.
http://www.youtube.com/watch?v=GX5kwVc9IOk
I know this is an LEO incident, but this could happen to a civilian as well.
So please, take advantage of any kind of training you can.
Edit: btw, they ended up catching the suspect...the suspect went home and wrapped himself in some carpet to hide. They sent dogs in the house who found him there.