Okay, so let's go over a few key details before we decide to continue on this rescue mission. Such as:
Who is she? What's she look like? What's the book look like? What sort of story are we delving into? And finally, how the hell do we get out after we've fulfilled the mission criteria.
I'm not jumping in there unless I know what I'm after.
mario is red, i am green, i try my best, but everyone's mean-Doc, remembering his long lecture during the deal with the Thousand Maws, grabs a towel for himself just in case-
Karkat's right. We need you to tell us anything you know.
What if there’s no better word than just not saying anything?Biker
Biker gets a lone message
"WHOEVER HEARS THIS IS A TWAT. sincerely, Doctor Bright"
Doctor
"... Her name's Clara. She's one of the scientists here, conducts tests. Mainly Euclid objects. She's got long red hair- dyed, of course- and green eyes. And the book... well, it's a long one, so we have plenty of time, depending on how long she's been in there. It's a fantasy, so we-we have an advantage in terms of weapons. And to get back, we need to find the book between the two bookends, grab it, and enter through any type of door. If we don't..."

-Finger to chin-
-Is there anything else significant in the hall?-
mario is red, i am green, i try my best, but everyone's mean