How does Huck escape the townspeople?

After the Duke and Dauphin have different versions of the tattoo on the dead man, the lawyer sends the mob out to exhume the body. When the $6000 in gold is discovered there is uproar. During the excitement Huck is able to slip away. He finds a canoe and paddles out to the raft where Joe awaits. Unfortunately the Duke and the Dauphin make it to the raft soon after.