When Vince Gilligan went on The Colbert Report appearance, Stephen Colbert brought up the lyrics of "El Paso" and asked if the blue meth is essentially his "Felina," his "girlfriend." Gilligan, pleasing Colbert with a Lord of the Rings reference, said: "I think he's coming back for his Precious and his Precious is the blue meth and the lab, the lab he constructed." Gilligan repeated that reference again in his interview with EW, saying, "He’s patting his Precious, in Lord of the Rings terms. He’s with the thing he seems to love the most in the world, which is his work and his meth lab and he just doesn’t care about being caught because he knows he’s on the way out."

Walt Was Already Dead

This theory, mainly from the New Yorker's Emily Nussbaum, but also posed by comedian Norm Macdonald, postulates that, as Nussbaum writes, "what we were watching must be a dying fantasy on the part of Walter White, not something that was actually happening—at least not in the 'real world' of the previous seasons." Nussbaum's theory is partly a rationalization for why Nussbaum thinks the finale was so discordant with the later developments in the storyline.

Much of the theory rests on an alternate reading of the episode's first scene of Walt in that snow-covered car. Nussbaum suggests Walt never really started the engine and instead froze to death. One point of evidence for this theory's plausibility, as one person offered in a Twitter conversation with Nussbaum, is that it seems like Walt broke the ignition lock when he was trying to start the car with a screw driver. If so, it might have rendered the key he found in the visor useless. The scene is shot in such darkness that it's hard to tell what exactly happens. We can see him toggling with the car, and something falling off of the steering column.

The next cut is Walt trying and failing to start the car again. When it won't budge, he seems to fall back, perhaps resigned to death. Steam escapes out of his mouth like the life leaving him.

Soon the car is illuminated with a police car's lights and Walt gets very still. He whispers "just get me home" as if in prayer. Macdonald writes, "He never made it out of that car in the snow, surrounded by police. That's where he died, his final prayer unanswered." The keys magically fall into his lap and he somehow is able to easily drive away despite the car being completely snowed in. Matt Yglesias at Slate pointed out that his ability to remove snow with just the windshield wipers seemed too easy when usually ice needs to be scraped off. There's a deus ex machina quality to that whole incident.

In her Walt-was-dead theory, Nussbaum points out that it would explain how he was able to evade the national manhunt and visit all the people he needs to (the Schwartzs, Skyler, Flynn, etc.) without being detected. "No one spots Walt when he enters Skyler’s home, either—or when he leaves," she writes. "No one notices when Walt goes to see his son for the last time, even though you’d imagine that area would be flooded with surveillance. Walt is not noticed even when he steps inside a brightly lit, crowded Albuquerque restaurant, where he sits down with Lydia and Todd." Perhaps the most ghostly moment is when you suddenly realize he's been in the room when Skyler talked on the phone with Marie about how he's back in town.