Getting back inside the library was probably more difficult than getting away from Rani. They had been trying for the past six days but the librarian was not budging from his place.
So they decided to get inside the library after it's closing time, which was 10:00 PM.
They knew it wouldn't be easy. But they didn't know that they would end up in jail at 1: 00 am.
They tried to get inside the library at 11:15 by lying to the guard that they had left their laptops inside the library by accident.
However this plan had one fault. The restricted area was locked up and the guard knew that laptops or any mobile device was not allowed inside that area. So he was not opening the restricted area which actually held the real deal.