He jerks away from the pipe. Reflex, from having been caught. He looks vaguely guilty, though he's fairly sure that no one would have thought to forbid chewing on pipes. These people don't even know about Mistborn, and no one here is paying any particular attention to him.

"Pica?" he asks, wiping a hint of saliva from his lower lip with the edge of his thumb. His eyes travel up and down the - man? - who interrupted him. He really has no idea how to interpret what it is he's seeing.