"Because they can't see us," he whispered back, trying not to glare at the poor girl--or to lose his concentration and drop the veil. "I've bent the light around us so there appears to be nothing here to see. Unless you freak out and go running down the street without me."
He cast her a quick, warning look, holding a finger to his lips as a couple more of the Toclaphanes whizzed by. "We may fool the eye somewhat, but there are at least four other senses."