“Sunk Costs” is able to perfectly balance the tension in the dueling Mike/Jimmy story lines being juggled on AMC’s Better Call Saul, with clear stakes for both our protagonists as they form powerful alliances and prepare to do battle with worthy foes. Mike’s machinations against Hector offer the most visceral thrills, but Jimmy’s legal battle against his brother promises the most twists and turns. Will Jimmy’s legal license survive? Will his relationship with Kim weather this latest storm?