He should shoot when he feels his life is threatened within the guidance published by the Boise State University officials. An ROE or rules of engagement should be published, posted on walls, school vehicles and in classrooms. They should be posted in English, Mandarin, Arabic and Spanish...Ebonics if necessary. The ROE should have threat levels clearly understood by all sides. They should discourage the use of the warning shot as a means to calm a situation as it may cause confusion and further expression of 2nd Amendment rightsl He/she should not aim to wound as this can endanger the life of the shooter and anybody else present. He/she should be proficient enough to fire two rounds center mass and then one round in the head from a distance of 25 meters.................. .........or professor X should kill himself for being such a friggen candyass.