3rd: They tell you that the memory isn't finished (and it's even labeled Part 1), but IIRC there's no indication that you need to go back to that door. I just assumed I'd find the other part later after getting Agate.
Oh yeah, I do remember it saying Part 1, but yeah, I just assumed the story continued in another Door instead of in the same one. By the time Agate joined the party, I'd totally forgotten about that. Still feels like poor communication either way. ---
