This sideboard is The Other’s lair. Prisoners draw tiles and move in the Hollow as they do on the Main Board. However, its shape is different. It wraps side to side, as the Main Board does, but not top to bottom as the top is an exit. Prisoners enter the Hollow when they fall into Pits on the Main Board. Upon entering the Hollow, Prisoners land in the lowest unoccupied row (Fig.1). They draw a tile to land on after committing to a space and then illuminate the surrounding tiles (Fig.2). There are several ways to leave the Hollow.

Red falls into the Hollow (Fig. 1) There are no other Prisoners and The Other hasn't started advancing yet, so they land on the bottom row (A). They draw tile a tile to land on and then illuminate the connected space (B).

Then Yellow falls into the Hollow. (Fig. 2) They must land on the second row, even though Red's draw has left open spaces in the bottom row. Yellow draws a Wax Eater (C).

Blue falls into the Hollow next. Blue lands in the middle column to avoid the Wax Eater Yellow drew. They land on a straight, orient it and draw 1 tile for the open space to the right (D).

Green falls in last and choses to land in the right column. They couldn't land in the bottom row because Red is in that row, even though the space is unlit.