Skyler and Walt spend a good part of the episode saying exactly what they mean, which in this genre counts as a plot twist. The smartest person in the room has a very public breakdown, and it is about as dignified as a cat in a bathtub. About 7 minutes of it is scenes you have already watched, in case you have the memory of a goldfish. Someone says "What does that mean?" with a completely straight face, and it works. For reasons the episode never fully explains, the father keeps coming up. Television at its most moreish.