I understand what you are saying, no one in their right mind wants to see another child loose their life or be injured, but I am also going to trust the teachers who have a better understanding of school environments and educational psychology on what the best methods to protect the children are. The point of schools is to educate children. Fear inhibits a child's ability to learn, so there has to be a better solution so that children aren't afraid of being hurt, but at the same time not be afraid because their school now resembles a prison environment.
My husband went over all the ways a school shooter could maximize casualties with me. Apparently open air campuses with modular buildings are safer especially ones that prevent students being crowded in hallways are much safer.
Apparently from what I hear, anyone can go to a gun show and buy an assault riffle. Why!? I think the first step is to limit assault rifles to military.