The intro basically tells you how to do it, there's a set of magic teleporting stairs on your right the second you enter the hall. Just beeline straight to it, with everyone. You will be teleported to the top of the map. Then you can just form a line in front of the stairs there and the fortune teller has no way of getting through. You just have to deal with all the people that will now bumrush you, but repeatedly using the weird book on two people that attack your line will mean only one person can attack at a time, so it's a huge choke point.