Rule 1. Fight to win
Rule 2. See: Rule 1
My Grandfather told me war story concerning a unit he was in during the D-Day landings.
After several days of heavy fighting in which no one ate and or used the toilet(stuck in a foxhole for 36 hours), there was finally a break in the action.
His unit was preparing to eat and the Sargent called everyone over to enjoy a well deserved meal.
One of the soldiers said he was ordered to guard 4 German POW’s and could not leave them unattended.
The Sargent took his pistol, shot all four POWs in the head and said, WE EAT NOW!!!! No one knew when the next meal might arrive or the fighting to restart.
My grandfather said the only rule to war was to survive, and win at ANY cost.
According to my very wise grandfather,The rules made by the Geneva Convention were for the lawyers and elites, not for those ACTUALLY fighting the war.
Sorry ... had to correct that for you.