As a military veteran, I understand the Geneva Convention and the "rules of war", however, there really aren't any actual rules once you are in a real combat situation.
The only real considerations that are actually abided by in conflict and real warfare tend to be things such as... don't overly torture note that torture in various forms still happens, some folks try to keep within reason for human rights.... with the exception being what happens to certain soldiers who might happen to get captured. Another thing that is watched for, but sort of ignored, is involving "civilians". There are times, and history has proven, that there are few actual non-combatants in and around places of conflict and war.
Let us not forget, that the majority of the countries and nations which are generally involved in various types of warfare have not actually signed the Geneva Convention, which means that they aren't bothering to follow these so called civilized "rules of warfare/combat".
Quite frankly, there is no such thing as rules or laws of war. As soon as you try to abide by them all, you end up getting your face stomped in. (I'll use some American history to illustrate my point). Take one of these "wars" Vietnam, Korean, French-Indian, American Civil war, and the American war for independence, all of these wars were fought with one side assuming that the other side would fight using the same general or basic strategies and ideas, and the sides that made those assumptions ended up having extreme difficulties and problems during those conflicts.
As soon as you attempt to apply rules or laws for combat within warfare, you will end up restricting yourself and your forces from being able to function to its fullest extent and abilities.
For those that might be interested in some of what actually happens to prisoners in war, talk to veterans and do some research. I believe many would be surprised at what kind of things are inflicted upon people. And honestly, knowing some of what I know and being strategically minded, I reiterate, there ARE NO laws or rules in war. Just as there are no real laws or rules when a person finds themselves in a true life or death/kill or be killed situation. When you are in that kind of situation survival instinct comes to the fore and many humanitarian concepts and ideas are shoved aside to make room for practicality.