NEA - it is possible to retto-fit schools to be rally, really safe.
The pic above is of Jim Bridger Middle School - located in the middle of Da Hood in North Las Vegas. IOW- a real pit.
Besides the full time **armed guards** - the school district replaced all outside facing galss with steel plate, all classroom door are solid metal with massive deadbolts and NO windows.
NONE of the outside facing doors have door handles and require a special key to open the door.
Most of the chain-link fence around the school is over 8 feet in height. Some of the fence has razor wire along the time.
My children were forced to attend the school - we called it Jim Bridger Jr Prison. Was it "safe" - I would say yes, based on the history of the place. The students were in more danger from other students than from the hood ratz.
My point is that nobody wants their child to have to attend a school that looks like a prison - but that is what it takes for the level of safety you (NEA) seem to be demanding.
Good luck on getting the funding to harden your existing schools....