Not everybody develops that problem. Buddy of mine was an artillery spotter in the Nam. He said he NEVER slept anywhere in any time in the vicinity of doing that particular duty ~ particularly during the rain.
And I’ll repeat:
“Most folks in a combat zone - not a rear echelon place like Bagram, but out on the front lines like this place apparently was, quickly develop that ancient reptilian disease known as Dragon Ass.”
If you think “In a combat situation chronic sleepiness is a special condition ~ it’s not like these guys are up partying all night you know. “, then it is time to back away from the keyboard and admit you don’t know enough about combat to express an opinion. Turn off your transmitter and go into receive mode.