come on man, more high schoolers die in car crashes (and probably a thousand other things) than school shootings
besides what happens when the shooting happens at home.
then what, bubble wrap them and lock them in a panic room ?
I can't disagree with you regarding auto crash related deaths, particularly among teenagers and folks in their early 20's.
While shootings do happen in the home for various reasons, such as domestic violence and suicide, they aren't usually considered mass shootings. Furthermore, a mass shooting is very unlikely to occur in my home. In my opinion, your scenario is far-fetched and it makes little sense.