The fact that all the video is from 1 angle is the biggest giveaway.
If it was good inside the box, there would be loads of footage from there. That would be a very unique experience, because all of these things are forced perspective. It's just the way a 3d scene being rendered onto 2d surface viewed in a 3d world works.

The water is probably abstract enough that it's not as noticeable, but I bet it looks weird AF (and not in a good way) when you are sitting in there