Vecna: eve of Ruin Web's edge question.

So i am running eve of ruin.  I am changing some of the stuff up.  I got that handled.  For the life of me I can't tell where the invisible door should be in the Web's Edge entrance.   The way the narrative reads it would be on the East side of the door in that open area in W1.   But if that's the case then everything else doesn't make sense.   

https://www.dndbeyond.com/sources/dnd/veor/the-wizards-three#W1FalseFront

i get that.  and perhaps i am failing my intelligence check.  but the narrative of the false area and the label of WI is on the east side of that door.   Why have the fake stuff out in the area where the bad guys are anyways.