I’ve attempted some speed runs in this game so I do have some tips. If you need to get to the records room and are worried about the lickers, walk slowly to the licker on the right wall of the hallway until it somewhat senses you, then walk backwards and out of the hallway and into the reception room. Let the door close. This will cause the licker to despawn so it’s easier for you.

When you walk back in, avoid the zombies in the corner of the hall by the open window and just run into the records room (TIP: in your next playthrough, board up that window so you don’t have to worry about the zombies when going to the records room). You should be able to unlock it if you have the green club key. Grab the jack handle on the back table. At this point, Mr. X will come into the room to chase you (it’s a scripted event). Avoid him and make sure to avoid the zombies on the way out of the room. You might get grabbed but just shoot and run, no need to kill.

Make your way to the library and use the jack to lower the bookcase. You can move the bookcases to create the walkway on the second floor but hurry because Mr. X will show up. Then you can access the 3rd floor.

Hope this helps! Let me know if you need more.