Originally Posted by
langleybaston
Like all the good questions, there is no good answer.
Historians have stressed that the most dangerous time on the battlefield is at the moment of surrender after inflicting casualties on the enemy. Once clear of those few seconds, the risk decreases rapidly, but never disappears. War makes murderers of combatants.
There is a good answer:
In non-international armed conflicts, Article 3 common to the 1949 Geneva Conventions and Additional Protocol II provide that persons deprived of liberty for reasons related to the conflict
must also be treated humanely in all circumstances. In particular, they are protected against murder, torture, as well as cruel, humiliating or degrading treatment. Those detained for participation in hostilities are not immune from criminal prosecution under the applicable domestic law for having done so.
My emphasis, Taken from
https://www.icrc.org/en/doc/war-and-...ed-persons.htm
Whilst I don't disagree that, in the heat of the moment, being taken prisoner is extremely dangerous for the prisoner, the law of armed conflict on this matter is entirely clear. If it is not possible to continue your mission with detainees, then it is definitely not acceptable to kill them. Simple.
Note : the above quote pertains to non-international armed conflict, but the law pertaining to international conflict is near-identical, with the only difference being that combatants may not be prosecuted simply for taking part in hostilities if they have remained within the law of armed conflict, but may only be prosecuted in the event they have committed war crimes.