A teacher could shoot a shooter right off the bat end of story.... However it's not the end of the story. A gun could be taken by a pupil and cause among other things an accident or God forbid another shooting. The teacher could be mentally unstable him/herself and either commit suicide or homicide. The teacher could have his/her weapon taken away from them and used against the students and staff. The teacher could miss while trying to confront a shooter thereby injuring other students and staff. A teacher could be mistaken for a shooter and or could mistake a SWAT team member as the shooter thereby either one shooting each other. Do I need to go on? A lot more could go wrong than right. And if implemented we once again would see the effects of our political folly.