The two shrunken girls, sophomores named Brittany and Samantha who have never met before today, crawl out from behind the bookshelf. After being shrunk, they were the two with the most heads-up reaction: as soon as they saw that Mike was distracted from hunting for the other girls, they ran from their carrels to the stacks of books, hoisted themselves up onto the first shelf, and snuck behind the row of books. Unless Mike had pulled out every volume on the shelf, he was never going to find them. It was a smart move.
Now, they've waited a few minutes to make sure he wasn't coming back, and it's time to figure out what to do. They're in a fairly isolated corner of the library, so the only place to go is back towards the main study area, where they hope to find one of their friends. Brittany and Samantha don't know each other, but the enormity of their predicament has forced them to rely on each other almost instantly.
It also helps that they have half an hour together before they even leave the first room. After that, it's a long walk down a hallway, and then they have to figure out their way down a staircase. If they manage to get through all that, though, then they'll be in the main study area, where they expect to find someone at least one of them knows. It's not optimal, but at least it's a plan.
The two girls start walking down the hallway, trying to focus on making progress instead of going with their natural inclination of staring up at the awe-inspiring structures towering over them. They make small talk, discussing their personal lives, classes, and plans for after college. After a while they even start to forget their situation.
That ends quickly though when they start to hear a steady clumping sound. As soon as they realized what that meant, they look up to see a giant confidently striding down the hallway, and right towards them. Brittany and Samantha have smartly moved off to the side to avoid being stomped by anyone who walked through without looking down, but it's still a terrifying moment. Just looking up at the stacks of books had been strange enough, and seeing an actual, living, moving person is almost incomprehensible.