With Walter engineering Gale Boetticher's replacement by Jesse, for reasons unrelated to competence or the daily 'business' routine, Gale falls victim to precisely the kind of political machinations and non-chemistry factors that made him leave academia and become a criminal in the first place, as he told Walter previously.
The book that Walt hands to Walter Jr. in the hospital waiting room is a hardcover copy of "Killing Pablo: The Hunt for the World's Greatest Outlaw" by Mark Bowden. Walter Jr. states that the book was a gift from Hank.
Walter Jr. says he is reading a book on Pablo Escobar and the agents who took him down. Bryan Cranston, who plays Walter White, starred in a film in 2016 entitled The Infiltrator (2016) .