Event: From Station to Station

Upon entry within the abandoned hub of the subway, one can easily observe the bleak atmosphere of the ruined station. It was a square lobby that was before the wide tracks of the would be rail. To the left were destroyed ticket desks and machines. To the right was empty snack and vending machines. Damaged seats, trash cans, and recycle containers also littered the place. There did not seem to be anything in the way of trains in this subway. Either they were taken apart, never there in the first place, or further down.

If one would take a look about, either barely on the walls or on the floor, is the subway maps of this would be station. It was a simple two-way station it appeared: The map is as such:

Stations:

B -> AB -> A
^
You are here

The rest is too damaged to read. Most of the other maps are similarly damaged.

The sharp eared can hear the snarls from deep within. Shadows perhaps? The source of the Prison? Regardless-there is only one method of knowing the answer.