There was one General killed in Vietnam, in the Army IIRC. I’m thinking his chopper was shot down while he was checking out some fighting.
My input on the OP is;
While, as has been pointed out several times already, anyone is at risk of having to pitch in at some time for a variety of reasons above some rank it starts getting rare. IMO that rank is Lt. Col. at the battalion commander level. If you are commanding more than a battalion you have just too many responsibilities, too many people relying on your keeping your eye on the bigger picture, and too large of a physical area to watch to be doing someone else’s job.
This is backed up by my personal experience as a Marine in Vietnam. Our battalion commander was in the field with us a few times, perhaps 4-6 weeks in total. Any rank above that was rarely more than a quick visit. As it probably should be.