Larian Studios Forums Divinity - Original Sin Divinity Original Sin - Help/Tips/Tricks off screen areas and locations [Hiberheim]

Here is a full picture of behind the sense map of Hiberheim. With one of the buildings circled.

I use teleport pyramid to get there and this is what it looks like inside.

What is this building is it a future expansion of the game?
When using the pyramid to get there the game start to freeze up in the upper corners of Hiberheim. The only place I have found in the game that make my CPU drop to 1-2 frames per second, even on the lowest setting.