I’ve had a surprisingly similar experience, in the army, although it was a Diemaco C7. I was following behind one of my conscripts on a live fire walking/pop-up target trail, as a safety officer, and near the end of the trail, the dumbass turns around, finger on trigger, full-auto and starts chatting with the rifle pointed straight at me.

I very calmly asked him to lower his rifle to the ground, then unload it, then tore him a new one. Then I went and sat down for a bit.