Very unusual event. In my 21 years in the Corps I never heard of a case like this happening. Fist fights in the barracks, sure, usually over women with alcohol and ego mixed in.
But to the death? Unusual. In spite of what Hollywood would try to tell you.
You would think someone would have heard something and try to stop it?
There was a soldier found floating in the river with a 2x4 thru his sleaves.
A captain was locked in a locker and tossed out a third story window. He wasn't dead after the first drop, so they took him for a second drop.
We knew of heroin dealers who were Viet Nam vets. They brought home a very dark side of that war.