You realize that if Marisa hooks up with Meiling she's going to use it to steal even more books.

EDIT: Anyways how about...

Mrisa ALMOST gets caught escaping the mansion by Sakuya or someone, but Meiling realizes that she's in a really bad mood and might actually hurt Marisa so she hides her. Then she can be like "Wait why did I do that?" and we can freestyle it from there?

Or something...