What does he think: The man was thinking about death, he was scared nervous and death was on his mind.
In the story "The Pit and the Pendulum" by Edgar Allan Poe, the character feels around the cell to see how large it is and where it goes.
What does he do?
We don't know much about the character other than he's locked in a cell and sentenced to death. He is a bit unstable, but when put in this situation, who wouldnt be. He is a philosopher which allows him to think deeply about the situation which helps him through the different obstacles throughout the story.