as founder of the library manip, he's a quick vid of how it's done. works the same as leon.

explanation is in the description but i'll post it here anyway, "shooting Anywhere on That side of the catwalk as long as it's before the end of the couch, it will cause the 1st zomb (if he's there or the sleeping one) to ignore an walk past you to the door no matter how close you get. im still working on how to manipulate the 2nd zombs pattern the way it goes in the vid since it's all fixed positions. but zombie placement has a chance to be slightly different (depending on what you do in rpd 1 library, im unsure) upon starting rpd 2. the furthest zomb does 3-4 things, in which the zomb will walk over to the door and stop at it or will continue walking all the way around the bookcase an somewhat make it's way towards you. upon walking to the door Turn around half way back round an somewhat make it's way towards you, which you may still have time or potential iframes from pushing bookshelf, OR will walk towards the stair case, which is what you want or stopping at the door. sometimes depending on spawn positions 2 zombies can even show up. the manip just turns it from a guaranteed flash/bite to Rng at this point. it's worth shooting an rollin the dice anyway since it loses no time doing so as appose to picking up & throwing a flash."

I was gonna type that I simply shoot at the floor right in front of the door(excuse the sick rhymes) and it works most of the time it seems, but yeah...Hippo gave a much more detailed answer than I could ever hope to.

I haven't really had to experiment with shot placement. Ever since I started trying this strat, I've made sure to shoot the ground next to the doorway and it works about as often as it does for anyone else which seems like 60% maybe idk. You'll know it's worked if you go through the door and the fat zombie do a loud growl as you run past him to his left. If he just moans a little bit like they do while in an idle state, it usually means it's worked and he's not tracking you.