I may not be as familiar as you are it seems. However I have multiple young children in my family amd some friends have children ranging from a few months old to teenagers. I certainly know how strong a five year old can be.
You should know that knives and bayonets have been used effectively in militaries the world over for over a century
But you know that and just do t want to admit it.
6 year olds are first graders and typically have very close interactions with teachers. It doesn’t take much for a 6 year old to stab through a person’s hand and into a person’s chest. Also my point is more thay the child could have taken a knife from thier parent as easily as a gun and then went on to stab the teacher. In both instances the result could end in death.
Knives are responsible for a lot of deaths and there have been mass stabbings in the news recently