Thank you! And [SPOILERS] in the library's storage room there's a padlocked trapdoor underneath a box full of books. To open it, just break the padlock with the fire extinguisher you can find in the reading room (it's at bottom-left corner of the screen). [END OF SPOILERS] For more hints and/or help (about this or any other A.P.P. game) feel free to join my Discord server, replies are often more timely over there.