Creative how they did that YT vid. It does look like the created a fake floor/ceiling, maybe 5 ft deep, and hid it with cheap faux wood paneling. Then by turning it upside and constant rotation, it is disorienting the viewer and hard to track consistency. You can tell everyone is crouching to make the room look bigger than it is. The actors do a good job of playing to the descending camera movement, which I'm pretty sure was done in post.
