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)
Answer: Saul is a criminal himself. It's not past his capabilities to forge some documents to show the 857k is available.
Ssiscool ★
Forged documents by Saul is most likely the correct answer.
The_Iceman