If you wish to argue for a situation that will increase that probability significantly, go ahead.
Maybe. These classes could be done using dummy rounds, right? Those are lethal only at very close ranges.
Needless to say, for these there would need to be police supervision. And, again, students would need to be screened before taking it.
This would also be fully consistent with one of the main original purposes of the 2nd amendment (having a trained militia that could repel an invader). It's definitely better than having civilians buying guns without learning how to use them, and what they can do to meat (this can be shown by the instructor), first.
It's grisly, harsh, but not insane.