Mentally follow this: keep your arms reaching the sky. Don’t drop your arms. Now, kneel down while keeping your arms reaching the sky. Now, drop on your belly while keeping your arms extended towards the sky. Now, don’t move a muscle and we will handcuff you.
It is clearer and more simple. It is way better than “don’t drop your hands or I’ll shoot you” and “crawl towards me (thus dropping your arms” so bang, bang.
arms reaching means arms extended way above your head.
I want to know how you lay flat on the ground while keeping your hands above your head unless you fall flat on your face. You would instinctively reach out to touch the floor to allow yourself to lay flat. And you would get shot for not keeping your hands above your head.