5. Hank Might Just Think It's A Coincidence, Put The Book Back, Wipe And Leave
It could happen. It might be incredibly disappointing. But it could happen. Despite the flashback to Season 4 just before the credits, and the look on Hanks face, which suggested he'd learnt something, he could just shrug it off as coincidence and leave. This in turn leads Walt to grow his hair back, and develop a scraggy beard, in order to travel across American to acquire an M60 machine gun from a car in a Denny's parking lot. Hey, it's just a theory.