Over the course of three previous seasons of AMC's phenomenal "Breaking Bad," viewers have watched Walter White shift from a mild-mannered chemistry teacher and family man into a ruthless, murdering criminal.

Walt's actions, precipitated by a cancer diagnosis and desire to leave his family financially secure, can't be excused because of his sympathetic backstory (in part because once his cancer was in remission and he had a nice nest egg, he continued his involvement in the drug trade). But at the same time, his actions have always been at least understandable (we do not condone!) on some level because at Walt's core, he is a survivor. In fact, his dangerous, destructive path demonstrates a primal "survive and advance" instinct.

When Season 3 of "Breaking Bad" ended, the science teacher-turned-crystal meth cooker was orchestrating a last ditch play to avoid being murdered by his drug kingpin boss, Gus (Giancarlo Esposito). In the final moments of that season ender, Walt (Bryan Cranston) dispatched his partner Jesse (Aaron Paul) to secure their survival in a particularly brutal way. This weekend's Season 4 premiere deals with the immediate fallout from that move.