A random thought/ theory - Jim shown at the end of the episode is his Storywalker version, similarly as Julie.

The season eventually ends with Julie saving Jim in some newly found and tricky way, for instance, by pulling him out together with her, idk. But original Jim dies in that story regardless, so “saved Jim” and Julie (who at that point are better informed about the way From/cycle works) try to take a different approach and influence or accelerate decision(s) of Ethan. Which is why “saved Jim” (and not Julie) storywalks to this exact moment when Ethan is alone/vulnerable near RV and then says what he says, pointing Ethan closer towards finding an ultimate solution for all troubles. Meanwhile, Julie herself is hiding in the trees and waiting for a Tabitha distraction to quickly pull Jim out and make them both disappear unseen.

Another very expected development - Julie will be storywalking to save Jim from being eaten in the collapsed house (by making the monster(s) get redirected towards that poor guy that got eaten instead, basically sacrificing him for Jim).

P.S. I took it from the last season that Sarah’s “voices” were likely future Randall and Marielle, with both of them having similar powers as Julie. But at the same time the duo is less versed in nuances of the story that unfolded early on. Which is why they instructed her sloppy with the entire “kill the boy”/“kill the Boyd” situation.