he had two options, 1. shoot the bastard, or 2. throw his gun on the ground and watch her die, unfortunately he did the latter, lucky for her she had magic to protect herself from the threat he failed to deal with even though the target was clear and open with no obstructions.
all this tells me about the MC is that he is a pathetic loser unwilling to take lives even if it means he has to watch another be taken.
fresh meat to the SDF or not, what exactly did he think he was training to do? hold hostile forces hands and sing campfire songs?