Hello, I found out, that you get an error-message, when you delete the goblin`s fireplace. Normaly, you shouldn´t be able to do so, but it helped me, surviving massive waves of goblins.
cheers,
TodAufLatschen
hey there @todauflatschen… thanks for the report… 
I am fairly confident this has been logged before (will search/merge later this morning when I’m at my PC)…