Standing there like a sheep at the slaughterhouse while he reloads? Some maniac tried this years ago at an Oregon high school and was tackled by an Eagle Scout, IIRC.
That really shocked me as well. A few tried to attack him but he was gunned down. This maniac was loaded up on steroids and very well prepared though.
One group with lots of teens just lay down unable to move and he shot them all in the head. You never know how you will respond to this kind of extreme situations.