Victor (Season 4, Episode 1: "Box Cutter")
Gus Fring was always the strong, silent type: Why should that be any different when he's in the process of murdering someone? Following his right-hand man Victor's failure to stop Walt and Jesse from assassinating genial genius Gale Boetticher, Gus calmly, methodically puts on a hazmat suit, extends the blade of a box cutter – and slides it not across the throat of the guys who defied him, but of the henchman who was proclaiming his loyalty until the very end. Gus needed Walt, who needed Jesse, so they both lived; muscle is replaceable, so Victor had to go. Take a look at enforcer Mike Ehrmantraut during that scene as he frantically tries to figure out whether to point his gun at Gus or Victor and you'll see that he got that message loud and clear.