This moment shows us that Llewelyn knows he is committing a crime by taking the drug money. Or is he just afraid the drug runners will fingerprint him? This may be Llewelyn's big fatal mistake; there's really no going back after this.

Llewelyn knows about the danger involved when he takes the money. That proves how persistent he is. Even though he knows he will always be on the run—you know, for his whole life—he still takes the dough. He is confident. Maybe over-confident.