Professor Truebridge and Professor Bunbury were already there and waiting as you come out of the Tunnel between the Willow and the Shack.
As if by magic.
The Shack is quite large, several floors, some are dry and light, other rooms are dark and damp. There are plants growing here and there and the old furniture is scattered around as if someone picked the shack up, gave it a shake and deposited it again.
There are strange whistling noises, creaks and groans coming from all corners of the building and there is a sense of something in the air like there is someone right behind you breathing on your neck.
Don't be shy, have a look around.