This is video of before the shooting where the angry black kid who would later commit the school shooting was out of control and attacking other students. You will notice the teacher to did not physically intervine to stop the attacks, truthfully she probably legally could not, but that is a major problem. It is a problem because as no one physically stopped the violent and out of control teenager he was able to continue escalating his attacks up to including shooting people in a supposedly gun free zone.
It would have been better to change the law, empower teachers to physically stop and restrain violent students in order to stop the violent attacks before they escalate to gun violence.