I don't know much about Kent State...didn't study it very closely.However,one would hope that the Guardsmen who fired did so on direct order (who was in command of that platoon and what was his rank?) or fired in compliance with carefully and clearly laid out "rules of engagement" issued at some point before the incident.
In other words, they probably felt it necessary to shoot, and took no joy in it.
I walked the area where the shootings took place with everything marked out. The nearest person hit with a bullet was about 100 feet away, the nearest person killed was 300 feet away and two were minding her own business on the other side of campus, killed by stray bullets. The soldiers fired on their own and the CO was suicidally brave, stepping in front of the soldiers to order them to stop firing while they were still firing. As mentioned they were weekend warriors in a real bad situation. Nobody figured out why they started firing.