Captain Seifert may have provided a greater service than most people realize.
The perp, sullen and resentful at being prevented from doing something we might never know, may have had more spectacular mischief in mind.
I believe he was planning
in the battlefield to turn against his comrades and attempt to hand them over to the enemy, his
real comrades.
Being prevented from doing so pushed him over the edge.
A battlefield execution would be totally appropriate.
I was always under the impression that "due process" in war is a whole other thing.