The Second Sanctuary sounds like an internal conflict between want, need, what you already have, & ultimately struggle. This even fits in with the themes of the game & Susie's character. She wants to be a better person for Noelle & her friends. She needs to be a better person than she is currently. She has already made great progress in becoming a better person being a completely different person than she was just 3 days ago. But she is still struggling with her emotions.

The Third Sanctuary isn't any different, but this time it applies for Ralsei. He wants to change the prophecy. He needs to learn that no one can tell him who he's supposed to be. He has already started understanding as seen with his hostility towards Flowery in Chapter 5 compared to how passive he was in the other 4 Chapters. But he is still struggling since he knows the story's end.

What they already have is also connected in a way. Susie used to be the strong one while Ralsei was the dedicated healer, but that has started to change too with Susie's healing magic (defense) & Ralsei's fire magic (offense).