This official video podcast, the last of the season, shows clips of Kate and Jack from 5×15 Follow the Leader, and also the key moments of the scene from 5×14 The Variable where Faraday says that they themselves are the variables.
Evangeline Lilly says it feels good for Kate to disagree with Jack.
Matthew Fox says that Jack believes that detonating the bomb has always been his destiny, and that completing his destiny is his only salvation.
Elizabeth Mitchell says she loves the theory that dropping pebbles in water changes nothing, but dropping boulders changes the course of the whole river. This is interesting, because she is referring to a part of Faraday’s scene which we didn’t actually see. Damon and Carlton said, in one of their audio podcasts, that the pebble/boulder bit, an analogy for how Faraday thought he could change time, was in the original script for the Faraday scene, but had to be cut because the scene was running too long.