It is a far cry from having zero security to making a school into a lockdown, prison-like, hermetically sealed fortress. Neither option is good. And despite all efforts, keeping safe from madmen lunatics is simply impossible.
I feel that yeshivos should have cameras anyway, but the recent type of tragedy is not why. Just think for a moment – we can’t prevent tragedies, but we can at least catch the perptrator afterward. Now that’s a consolation. Now, I feel better.