Ohhh, I see! That scene, where it flashes back to Gandalf recruiting Thorin, does two things. (1) It recaps the mission, but importantly, (2) It gives us more context on Thrain. In the original Desolation of Smaug, it makes sense because it serves both of those purposes. But actually in AdamDens’ 2FS (which I love, obviously!) it kind of doesn’t work for the second purpose, because Thrain has already been discovered at the end of the first half. So when making this a TV series, I reasoned that if the show had been made this way, the flashback would mainly be used to reintroduce the viewers to Thrain, in the episode where Thrain is rediscovered.