Portland Mall Shooting

Do you think malls and theaters and schools should have some sort of shooter back up plan?
I know schools are short on funds but malls and theaters I would think could afford to employee some sort of under cover special opp's or secrete service type of Securty that could be a first responder in the event of crazed gun man on a rampage.

Would you feel safer if you knew the place you were shopping or watching a movie at had a trained undercover first responder close by? Im not in favor or supporting troops with armor and machine guns marching around the mall or sitting next to you in the theater. I was thinking more of a undercover Air Marshall style guard that could possibly stall or prevent a mass shooting