Turgon has absolutely no desire to be in this fight. He's there as canon fodder for his father's disposal and knows it. As such, he lacks all skill with modern weapons and leaves the fighting for the soldiers who know, relish in, or otherwise have some idea what they're doing in this fight.
Having the wisdom to stay behind, Turgon slides into the background and sets about helping others who are conscious and need an escape from the line of fire.