Digging yourself out of the ground with chopsticks in your mouth is impossible.

It could happen

The movie is not a documentary about self-exhumation.

Why not? I always figured he scratched away enough earth that he could wiggle his neck around, which would loosen up more earth around his shoulders, and so forth until he just wriggled free. I assumed that only the first few inches were chopstick-dug.

They missed an easy joke as Jackie Chan was leaving:

Wilson could have said "but I don't know how to use chopsticks!"