Training is inherently dangerous, especially for those in Special Operations community. Accidents happen. Before I went to BCT at Ft. Sill, a Arty unit doing training dropped a 155 round into a Basic Training Battery in evening formation killing several Privates and a Drill Sgt. When I was at Medic school, we had a guy nearly die during FTX at Camp Bullis because he walked off the edge of a ravine. God bless those injured.
I doubt there was any Army/Marine basic training company in the 60’s that didn’t have a “Fire in the hole” dropped grenade event on the range.