Both yes AND no, because of upsides and downsides to this

First of all, no, teachers, or at least certain teachers should not be permitted to carrying firearms in school buildings because there could be the possibility that a teacher could let loose their anger upon any student or group of students at any given point in time, and giving teachers firearms would put students who have a teacher with anger management issues at a larger risk, because that teacher could open fire on a student(s) who made the teacher snap via purposely or accidentally doing something wrong, and at still more risk it that teacher is able to hold back their anger a bit, because other students in the class, or in a previous class if in the case of middle schools, high schools, colleges, and universities, because those other students could have riled up the teacher, and that last student(s) being the one to put the final nail in the coffin, whether it be accidentally, or purposely. This would, again, cause the teacher to finally snap, and enter a possible uncontrollable rage state, and with the presence of a possible easily accessible firearm, the teacher could shoot said student(s), or a different student(s) of their choice, on top of this, students could gang up on the teacher and steal the firearm, possibly using it to kill the teacher. On the other hand, teachers, or at least certain teachers SHOULD be permitted to carrying firearms in school because in case the security guards or police or whomever would be standing guard at the school building wasn't enough to hold off armed criminal personnel attempting a school shooting, the teachers could tell students to run, but could also tell them to not go far enough to where they wouldn't be able to see what was happening, if the students are older and more capable of withstanding the trauma of seeing someone get shot, so that if the criminal is eliminated, the students could come back if they saw this, or continue to run if the shooter succeeds in killing the teacher, and on top of this, if