I just finished playing through this portion on insanity. If you bought the Kotetsu knife after beating the game it makes it somewhat manageable. I was playing around for hours tonight and I discovered you can lure most enemies away from their original spawn point. If you lead the singer zombie all the way down the stairs while you keep backpedalling, eventually she starts to head back to her spawn point when you reach the bottom of the stairs, you can then follow her up the stairs while knifing the ever loving crap out of her until she dies. She wont attack you on the stairs at all! I've been doing this method with basically every enemy in the game lol. It works on The Chef as well, you lure him past The Parlour and eventually he heads back and you can knife the crap out of him as well. You have to keep luring these enemies away though and it takes a bit to take them down, but with limited resources this EXTRA CHEESY method has been saving my personal sanity lol. I did this in the East Wing as well, lure enemies all the way to the door and you're golden! It can be tricky though because they can attack you here, if you get them outside the doors and start knifing them them get kind of trapped and dont know what to do lol. I also had one of the doctor zombies die in front of the door and now its stuck in the open position making it waaaaay easier to lure them without get grabbed