You wake up in a cell crawling with vermin.
The walls are wet and slimy and there are no windows. Small wet things squiggle around on the floor. The air feels like you are trying to breathe thru a sponge. Occasionally you hear a faint whimpering mixed in with the constant dripping and gurgling.

The door looks like it is not quite closed.  If you want to, you can push it open a little

The wall has a section where it looks like someone has been scraping the mortar away from between the blocks. If you worked for a couple hours you might be able to move the block.

You can choose to...
    search the cell more thoroughly
    try a magic spell to open the door 
    rush at the door and slam it open