If he sets a mind on fire, the only way for the mind fire to go out is for him to put out the fire or for the mind fire to run out of a mind to burn. None of those have happened, so he is very confused.
He can see their emotions, which are a byproduct of their mind. It meant that this was not a robot. This was a hale and hearty person who appears to have made preparations to deal with his ability.
His sneer of ridicule changed to a frown, and he began entertaining the thought of a retreat. The man was fast, but Thorin was faster. He could still run and escape if he did so now.
He stepped back to do just so. But then he felt his stamina leave his body in a large burst. His body sagged as if he had just exerted himself physically. He became so weak that he stumbled.
His frown changed to shock. He said, "I know this ability. Are you the Count? But that's impossible. You are supposed to be dead."
