All political arguements aside.
First and foremost, this killing by a 9 year old is a 'Health & Safety' in the workplace issue.

Sadly the instructor has payed for his, and his employers, negligence with his life.
This may also now become an insurance and expensive lawsuits issue..

Bullets and Burgers !!!???

If this was not already actually happening in the real world
it would be a near perfect imaginative construct for a satirical comic book & movie franchise.