The tree-monster is just too powerful to overcome, and Zeke is nearly killed by its attacks. Justice is knocked out before she can reach the tome. Zeke makes his way over, rousing her so that they can try to escape.
Justice resists, unwilling to leave without the book, and he has to drag her out rather than leave her to die.
Once they escape, Justice has a moment to recover, and apologizes for almost getting them killed. Though dejected over not collecting this new book of knowledge, she’s still confident she knows the purpose of the Pontifex, so maybe it wasn’t all for nothing.