From our government; If a person starts shooting. Run and hide. Ignore the wounded, don't worry, when the police arrive they will ignore them also. Above all else, be passive and submissive. As a last resort, you can use a pair of scissors to deflect the bullets. http://www.youtube.com/watch?feature=player_embedded&v=oI5EoWBRYmo In a sane world, it would be; Find cover. Unholster your firearm, check to ensure safety is off. Try to determine the location of the shooter. If he comes into view, shoot for center mass. If he points his gun at you, do not stop shooting until you are absolutely certain he is no longer a threat, or you run out of ammunition. Go immediately to the aid of victims, direct calls to ambulances. Call the police so they can file a report. Go back to work.
Not a big fan of the "Leave the wounded behind" recommendation. Who knows how long the stand off might take. You're gonna let someone lie there and bleed to death? I hope a teacher wouldn't take this advice and leave a wounded child that they can easily carry/drag behind.
