Tyther had a dead serious look on his face. "Your heart. It's beating really fast. What more proof do you need? Also, you're sweating a bit, and it's air-conditioned in here. And it's night-time. Look, if there's some big secret, that's fine with me. But you either tell me now, or I'll just end up finding out later and probably almost die." He softened his gaze. "If it's that important, I promise not to tell anyone else."