There is an air of oppression in this guardroom, a steely-eyed cultivation of the premise that if one does nothing wrong, one has nothing to worry about. Yet a few small cues allow you to see through that flimsy lie. Bits of rope cling to a sturdy, uncomfortable chair where someone was questioned, none too gently, and though the floor is clean, a quick examination of the mop bucket used reveals a thin residue of blood around its rim.