Look at 11, then 7. You can see it in 11. It's some kind of duct or something hanging from the ceiling. Then 7, the camera is much closer to it further down the steps.
>>17525954 (me)
Sorry, been a while since I made this and looked at it closely. I remember identifying that thing in 7 in another camera. I'm not quite seeing it right now though but I recall I was able to mark it as some feature from the ceiling