D&D - The Dungeon

You enter a huge open entrance to find yourself locked in.. and the water level is rising. How long do you have before you drown?
I created this piece with this scenario in mind, a massive dungeon slowly filling up with water, and the players panicking and trying to find an exit.
It being for my homebrew D&D campaign, I also added some bits from the theme song (another score I published), to spruce things up a bit!