PP 4-6 of paperback The Departure, Book 19: The Animorphs are spying on a meeting of the Sharing when they suddenly notice that a Human-controller is being arrested and dragged off to a Bug fighter to meet Visser 3! They decide to rescue her in the hopes that her Yeerk would be grateful enough to reveal secrets to the Animorphs.
How did the Animorphs intend to keep that Yeerk alive for more then 3 days so that they could debrief it completely? I am confident that the Yeerk won't cooperate unless the Animorphs have a source of Kandrona rays for it.
