Revealing mistake: Walter is in the basement and slides two bottles of water and a plate with a sandwich across the floor to give to Krazy-8. Right before he slides the plate across the floor, the camera wobbles slightly. (00:28:25)
Revealing mistake: When Jesse puts Emilio's dead body in the bathtub and we see a view from below, Emilio blinks. (00:42:27)
Revealing mistake: Emilio's eye twitches when the gun is dropped on the bottom of the bath next to his head while he is supposed to be dead. (00:42:54)
Chosen answer: It is part of the ritual for la Santa Muerte. It is a sign of humility and sacrifice.
djm