I disagree.. ONE grown man with a legally concealed gun and/or a bright flashlight could have stopped several murders in the Colorado Movie Killings... By All Means, Hide Behind something that can stop a bullet, but do so in order to advance ur postition to improve the chances of your handgun neutralizing the threat that is attempting to kill women and children..
Just added something that would greatly aid your cause. Especially in the theater scenario.
I never though much about carrying a flashlight until that theater shooting in CO. It would have been the most effective tool to use in that situation coupled with aggressive action to subdue the shooter. But all hard charging, guns ablazing, is not usually going to end well for the good guy. YMMV.