Factual error: When going over the logistics of the plan to kill the ten men in prison, Jack tells Walt that killing Osama Bin Laden was less complicated. Breaking Bad takes place over a period of two years, beginning with Walt's birthday in 2008, and ending on his birthday in 2010. Bin Laden wasn't killed until May of 2011. (00:15:23)
Continuity mistake: After Pinkman opens the bags filled with money he throws his gun along the floor. When it stops it points in a 3 o'clock position. When the angle changes it points in a 1 o'clock position. (00:41:00)
Visible crew/equipment: Walt just ordered to kill all Mike's witnesses in prison. While it shows one of them stop in front of the locked door and get killed by the other prisoners, a cameraman is reflected in the glass door.
Continuity mistake: In Season 4 we see Mike gets shot in the ear and and has a flap of flesh hanging off. In this episode, there are no marks or deformities on his ear.
Chosen answer: It is part of the ritual for la Santa Muerte. It is a sign of humility and sacrifice.
djm