I was never held as a POW, but I’ve always had the impression that POW camps featured armed guards, fences, and sometimes even machinegun towers. All this gives me the idea that lethal force, at some point, is what allows a relatively few guards to keep the POW’s captive.
Did you ever notice that those machineguns are pointing out? Those guards are still combatants and can be attacked by other combatants.
Soldiers executing a raid on the POW camp can use all the lethal force they want against the guards. The POWs being rescued, however, cannot join in the attack. They cannot pick up arms and attack until they are returned and reintegrated into their units.
The guards cannot legally use lethal force against their prisoners simply for escaping or attempting an escape. I’m just tellin ya what the rules say. I’m not naively suggesting that every country on Earth follows those rules.
Perhaps not quite the same thing, but it reminded me of a story of four Poles who managed a (pretty ballsy) escape from a death camp, by donning SS uniforms and nicking a car. The guns they took with them would have been used only on themselves in the event they were rumbled before leaving, as they didn’t want a doomed escape to harm anyone left behind in the camp.