The Doctor shrugged when she asked his opinion of Sam. If there was anything the Doctor knew well enough - it was that one does not question the current appointed leader unless absolutely certain they were thick, incompetent, or otherwise unsuitable. For now, Sam seemed well enough for his post.
"I did hear about the body," he said quietly, trying to set back his momentary insecurity to the back of his mind. He still hadn't heard from Martha. "That doesn't mean we won't get out. It could have been one of those animals that was set lose that did that. I'm not so quick to assume that it was whoever is behind this that did that," he couldn't assume that; not yet. He didn't have any evidence that they did whatever to that body.
"Sometimes I'm too busy to listen - it's this thick head of mine," he smirked a little, "Too full of memories and thoughts and plans to work properly sometimes. It's like my ears close up."
He was piecing together in the back of his mind the things she described about the noise and a smoke monster and whispers and this creature didn't sound like anything he was familiar with - which made it actually seem a bit less threatening.
"No one is ever useless," he said rather pointedly in a tone that didn't leave much room for argument.