After the events of Order 66 in “Revenge of the Sith” and his battle with Darth Sidious in the Galactic Senate Chamber, Yoda chooses to exile himself to Dagobah for a reason when Luke first meets him in “The Empire Strikes Back.” The remote swamp planet has an exceptional connection to the Dark Side of the Force, allowing Yoda to remain undetected. When Luke is told to wander down into the Cave of Evil, he sees a manifestation of his worst fear, defeating a vision of Vader only to find his own face staring back at him.
In “The Last Jedi,” Rey also has to confront a strong Dark Side presence on Ahch-To. She is looking for answers about where she came from and who her parents are. Instead, in another instance of “Star Wars” poetry, Rey only sees her reflection. She is alone and finally accepts that stark fact.
For Ahsoka, her experience is entirely different and unsolicited. Instead of remaining unattached, she lets her friends and her unresolved grief about Anakin turning to the Dark Side get the best of her. As a result, she falls to her supposed death after battling Baylon Skoll on the cliffside of the planet Seatos. Ahsoka isn’t seeking atonement, and her sentimental reunion with her fallen Master isn’t really a lesson at all. It becomes a confrontation with what Anakin became, allowing her to finally come to terms with his tragic downfall in much the same way that Obi-Wan Kenobi was finally able to put his guilt to rest in his own, short-lived Disney+ series.