//anime spoilers(?)
I think it's amazing, excellent even, the anime's choice to exclude Kiriko from this moment. This is entirely Roji and Muhyo's moment.
Roji must find the book because Muhyo is believing and trusting him to do this all on his own. He makes his confidence in Roji's abilities known, which gives Roji the push to jump. In the anime, when he's afraid and nearly at his limit, Muhyo is the image that he conjures to reach out and makes a promise to keep going as his partner. It's a moment where through Muhyo, Roji finds his strength to continue to go deeper and better himself. I also adore that once Roji finds the book there's a visible relief from Muhyo, his trust has increased and they have truly become a team that can rely on each other for strength, even when they're apart. Muhyo even came to sit next to Roji after everything and they shared a nice moment. Beautiful execution of this chapter by the anime.

