I'm surprised no one has ever thought of this!

I watched this movie and couldn't help think that he could have dug his way out in some way or the other. One of the things that first sprung to mind is to push one of the sides of the coffin with his feet until he could let sand seep in and push it to the other side of the coffin with his hands. Before doing that, I would actually take out my shirt or any cloth I have and tie it on my head to somehow create a vacuum in case sand comes from the top. And he could have done that by turning around and crawling on his fours, he could have easily done that in the coffin, instead of laying face up waiting for sand to bury him alive. Why not go on all fours and use your body to allow the sand to fall around you? The place wasn't that tight.

It was really frustrating for me to watch him die, as I actually thought he'd figure a way to get out of there. He could have tried to let some of the sand seep from the narrow side of the coffin and push it away, especially after he was told he was not far from surface. This would have removed some of the sand around the coffin and would have created a vacuum that 'swallowed' the sand and facilitated his way to freedom.