This chamber, a full 30 feet below the Upper Dungeon, isn't made of stone blocks, it's hewn from the living rock of the earth.  10 by 15 feet, its domed ceiling and walls show the tool marks its excavation.  There are numerous lines of filth on the walls marking the various levels that water has risen up the walls during previous rainy seasons.
The Lower Dungeon Guard Room, Dungeon
murderer
prisoner
I am a prisoner who broke the law too many times. I am from a poor village. I was running with a bad crowd from a young age.
Oi, what you in for? Come on, I'm dyin' o' boredom down here...  Well you see, you would think I murdered someone but it was actually petty theft.  Ha! What did ya try to nick? Someone's life, was it?  You know me so well already, what brought you to this god forsaken dungeon? Peddlin' my special blend of herbs and spices, if you know what I mean! Wanna share? I'd like to have a friend in this god forsaken place... Oh! May favorite herbs. The Devil's lettuce. Whatever takes me away from this reality. Say, have you ever.... well... considered breaking out of this place? Of course I have. Ol' pirate in the other cell has a plan but he isn't all there. So take it with a grain of salt. What was his plan, if I could ask? I've been mulling over my own... Some inspiration might help... Speaking of inspiration, could you pass back the herbs? I could use some more... He was going to take his peg leg and try to excavate his way out.  What if we.... Am I crazy? I can see there is water damage in this dungeon. There must be an opening somewhere to the outside. Maybe if we... You think it can be done?