Character mistake: When Hank is brought to the hospital with gunshot wounds, the ambulance and its two EMTs are met outside by two doctors. One doctor says "Let's get him two grams of oxygen. What's his hemoglobin?" This episode's technical adviser was perhaps away for this scene. How much exactly is two grams of oxygen? Orders for administering oxygen would be given in liters, such as two liters per minute (LPM). The line is presumably meant to be 'two liters of oxygen'. (00:02:25)
Continuity mistake: When Walt is talking about his operation, in the hospital Cafeteria after Hank is shot. He says the line "Lying there waiting for them to anesthetize you." From one angle, he is shown looking forward, while from the next angle, he is turned around facing Marie. (00:20:50)
Chosen answer: It is part of the ritual for la Santa Muerte. It is a sign of humility and sacrifice.
djm