Originally Posted by Frozen Fireball
Well, hearing is like sighting. It improves detecting enemies as a red dot on mini-map.
I thought there's no way to free them. But I saw the last post of this thread: ( Some minor spoilers )
http://www.larian.com/forums/ubbthre…&Number=438753
in Larian forums which says if you don't kill the soldiers and then kill the wizards later in the game , they get free. Although you could use the XP you get from killing them.

On the Faq from GameBanshee they say :
http://www.gamebanshee.com/divinediv…thoverview.php
21 - Military Camp

When you walk far enough into the camp, three evil wizards named Cornelius, Josephina and Antx will take over the minds of the soldiers and turn them against you. There isn't any way to cure the soldiers, so go ahead and kill them all unless it makes you feel too guilty. You'll meet the three evil wizards again