No.
Wouldn't have made a difference.
What are the odds that if it were completely legal, that one of the students in that classroom would have been carrying a gun, knife, etc... that they could have accessed quickly enough to make a difference?
The students would have had more of a chance had several of them been trained in close hand-to-hand combat with a focus on disarming an opponent...But then that is as equally unrealistic as having armed students in every classroom.