Setting prisoners on fire and using them as human shields is a<em>bit</em>over par for the Imperial guard, but not by that much.  That an NCO evidently can get away with this kind of behavior suggests that the commanders of the Imperial Guard regiments in the Ares system aren't very good at their jobs, and/or that they don't expect anyone to ever surrender to them.  The 9th platoon is clearly an assault platoon, likely one repeatedly sent to the front of engagements, and one that took heavy losses when the station was captured