So, I am just having this crash when trying to leave Hall of the Unseen, to the surface

 

Here are the crash log files:

 

01-17-2019__19'57'26.zip

For what it's worth, I was able to resolve this with the Steam option to "Verify Integrity of Game Files." 

I have experienced this also. The same workaround worked for me.

 

Alternatively you can go back to a previous save (when not on ironman) and try HoU again.