Room 7/10 is a long hallway stretching east-to-west. The western end opens through a secret door while the eastern end contains a giant-sized mirror that is a portal to elsewhere in the Tower. An empty umbrella stand sits next to the mirror.
The hall is lit from every surface, managing to obliterate all shadows inside. Any attempt to move down it makes the hall seem to stretch infinitely. After a few dozen steps, the light gets overwhelmingly bright and any adventurer inside must make a saving throw vs spell - on failure, they are blinded. If one throws a shade over theirself, such as with an umbrella, they can walk down the hall with no issue.