HOW CAN I GO DOWN THE TRAPDOOR?

You will need a new ladder.

You've seen one around.

Go to the library and take the ladder.

It's not tall enough, though.

You'll need to attach it to the wall or it too will fall down.

You'll need some bolts for this.

Luckily you can find some in this room.

Use the wrench on the mannequins with bolts protruding out of them.

After taking two bolts, you can now use the ladder to get down.