The title of the song refers to a line from The Count Of Monte Cristo but Alexandre Dumas where Dantes' character is thrown into prison.

The line is below:

"He descended fifteen steps, and the door of a dungeon was opened, and he was thrust in."

Following the story, this is a bewildering moment for the character Dantes.

When knowing the story and seeing the song lyrics through this lens, they make sense and one can interpret it rightly on their own.