It looks as though it was a controlled descent. The arms are tucked in to reduce its upper body width. The leg hangs on long enough to ensure going through head first. The second picture might even be a kick to really force the orientation of travel.

If you are a creature who is falling through a hole, maybe going head first is a pretty good tactic. Once you get to the bottom, you can crawl forward, possibly burrowing along the ground under the fabric as you crawl.

The alternative of your rear end facing down and your body folded in on itself could have meant getting stuck. Ingenious creature.