Other officers say arming everybody makes it harder for them to tell the good guys from the bad guys. “And when you have multiple people potential pulling out guns, that's gonna totally go against our training and potentially create a chaos that we may not be prepared to handle," said a police officer in the audience.

The only configuration that will actually work in the 'Columbine' scenario is to have armed 'good guys' on hand and ready to go. That means teachers and students. Perhaps you need to change your training to accommodate the effective configuration.