>>138967>>139007Chapter 4 was a "Bonus Disc" distributed at a convention for free (or for dirt cheap, I can't remember which), this is why it's short and relevance to the overall mystery is low. But it still does have one really important clue which is showing that Rika is aware of everything that's going on and she controls her own "persona". Prior to this it seems like she is possessed and she can't control it, in reality she's just frustrated from not being taken seriously in the hundreds of prior fragments.