Larian Studios Forums Divinity 2 - Ego Draconis (English) Help/Tips/Tricks Broken Valley after gaining access to Battle Tower

OK, i got into the mine, got the sigil, but I also got a lever handle, and cannot find what it goes to. There is a spot on the map farthest south that seems to hold more area, but I can only go so far. There is debris in the way. I know the handle does something, but where?

long time since I play last time
Wait for Raze

In the far eastern room there is lever socket on the ground. There is not a huge reward, though.

In the southern tunnel, the western branch has a hidden room at the end. I don't recall anything extra at the far southern end, though.