Have you ever tried something you thought "looked easy'...but when you tried it...it was extremely hard? For me it was water skiing. I thought it was easy because I lacked the knowledge of water skiing. I will try my best to explain why the 2 options I mentioned are our only choices.
1.) You have to have metal detectors...because once a shooter has entered a building...they have the upper hand. In that you must come to him rather than him coming to you. Not to mention, they can kill 30 students in a 1 classroom in seconds.
2.) You have to have a minimum of 2 armed security at each entrance. if there is just one...shooter has the advantage of surprise and kill the single guard. Now refer back to 1.)
Why do you think courthouses are set up this way. Also...courthouses have more security than I mentioned. They also have armed security on every floor and on patrol in the hallways. Do you think they do that for a real tactical reason...or are they just wasting money?