The special forces elites of the 10th Brigade didn't have the same terrifying battlefield dominance as the Interstellar Warriors. Despite the armor plates welded onto their exoskeletons providing protection for their vital torso areas, they weren't enough to completely ignore enemy gunfire, let alone the significant number of laser weapons in the hands of the elite Honor Guard of the Kingdom of Stefano.
Their offensive tactics, relying on laser guns and electromagnetic rifles, could easily destroy ordinary soldiers, but when facing the few Sentry Mecha, they too lacked effective means. Only their most elite, trained to T2 level, holding anti-tank rifles could pose a conventional threat to those 'Knights.' Other special forces elites needed to either get close with chainsaw swords or plant bombs, or otherwise hope to have anti-armor rockets or mortars at hand.