It's not just that the next passage, you suddenly realize, needs some structural support from the scene before, though that's common enough. Reading them in rapid succession often makes things clear that weren't when you wrote them a week apart.
But it seems like the muse needs to mull over revisions, even, and brightly observe afterwards that really, ensuring the heroine went the right way should not be entrusted to the word of a man she doesn't trust, and it would be much more smooth if the road only went one way.
And only after that is written up does the muse comment that actually, there's a sound reason why the road only has one end, and the heroine even has a chance to guess that people -- and places -- are vanishing from here, especially since it's going to be important later on.
Without, of course, making it clear when she figures this out, so I have to decide that it's late enough to keep her from running away from it all with her new insight. . . .