Thanks for the detailed answer! Good to know the walls are on purpose. Saying it on the page would have helped me.
The shadow in the light was on floor 3. Its eyes moved over the lit area and just floated around me while I was standing in the light. For the flash, I honestly don't remember if the torch was already cracked, but if the flash shrinks with the cracks, that's probably what happened. A small hint when the flash gets weaker would make that clear.