It was a bad idea. Back in the Saintess's castle, Servius tried to bump his entire body as a small mouse to the curves of the transparent crystal vase. He tried to push it to the edge. As he couldn't possible remove the book that had captured him inside the vase, he might as well break it to pieces! It would be dangerous considering he is still a small creature who would be affected if he fall from such height surrounded by sharp shards that would be probably bigger than his own size.
But he couldn't pay much attention to it now.
After all they are in danger! Not only is the Saintess insane— her own twin sister— Isabelle was not that much different! He regretted the idea of bringing Isabelle to the Black Dragon. He also regretted that he had trusted Isabelle so much merely because she appears to be having an opposite goal to the Saintess.