It's not as though Merrill's love of griffons and griffon tales has ever been kept secret. Her gasp is one of excitement, and while it would be perfectly logical to think that it's just Merrill being Merrill...

"So you're the one who took the books from the library! Of course we're not leaving if there are griffons."

All that defiance, gone in the face of griffons and the fact that some books about them weren't dusty.

...Wait.

"What rumors?"