Perhaps you could use a different material for the thin walls, perhaps wood. You could probably justify eight inches for a wood partition(which would be quite stout), in an area where hewn stone walls would make no sense.
Speaking of wood, the grain on that table is quite out of scale, making the table look tiny. While a realistic depiction of wood grain at 10-feet-to-the-inch scale wouldn't be very appealing, a smaller grain might help.
Also, while the referee might rule against you, there is no way you can corrupt this dungeon layout more than the random number generator already has.