In the beginning of Khatyn, we are introduced to a man with dark glasses and a white cane whose "mouth quivered with the guilty smile of a blind man." He's later said to have the "fixed quiet smile of a blind man." I'm slightly baffled by this. For one thing, they appear contradictory to each other. For another thing, why would a blind man necessarily have a "guilty smile"? Can someone explain these quotes to me?