The Shadow IRL

[Googolplex]

This is not in a sewer, I think this is just a further fake of America like all the alien bodies etc.
This looks like a physical examination of some vein. When you look at the environment, the objects are very small, the water animation is just in micro zone. The camera also looks like a micro cam for doctors who examine human bodies (in most cases veins).

This really doesn't look like a sewer. It's not in a dimension of 3x3 meters.