why execute them? he's probably just some poorfag in it for cash because he sucks at everything else. give him some menial labor job he can't sabotage for a pittance and slowly interrogate him. do that for a few years then send him back to his home country. if it creates even the tiniest bit of goodwill maybe they'll spare some of your own pows in a similar situation. every soldier that isn't a conscript is a mercenary essentially.
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