For a certain type of Star Wars fan, .
“I don’t really think of it as time travel,” Filoni said. “It’s not really a thing where you go through one door and out another in a different time. The World Between Worlds is really about knowledge and gaining knowledge.”
In the context of these new Ahsoka leaks, that makes a lot more sense — although it still doesn’t totally explain how Ezra was able to save Ahsoka’s life via the World Between Worlds. We’ll just have to accept that he was destined to do it, or whatever.
Ahsoka in the World Between Worlds
Based on all this, it sounds like the Mustafar scene in question in Ahsoka won’t exist as something that actually happened (or will happen), but rather as a way for Ahsoka to simply gain the knowledge that no matter what she did, Anakin would still have turned to the Dark Side.
If that’s what Filoni has planned, then our understanding of the World Between Worlds (and that episode of Rebels) could change dramatically very soon. Leave it to the guy who introduced time travel to Star Wars to finally explain how it actually works.