Mark's still leaning against the wall, paying a lot more attention than it looks like. Part of him is keeping up a running mental narration to Grissom's work, and the other part of the brain is asking all the questions he's dying to know. "Is it possible that the bug came from some random passer-by and latched onto the corpse? How the hell can a dead body lie in a woods for sixteen months without anyone finding it? Wouldn't it smell? Wouldn't the person in question's family or friends miss them before then? Why wasn't a better search conducted? Why are people that stupid? It's probably good that he keeps his mouth shut, though.