Windwall Outskirts design flaw (impossible to follow tactical advice)

[Razer]

In Soul Harvest you get to the Windwall Outskirts and have to duke it out with some dwarves. Harratir has some briliant advice to build a tunnel to flank your enemy and skip a part of the map. In order to do this you must travel through a temple ruin that takes you from the bottom of the map to the top left of the map. So far so good. Now in order to build a tunnel exit you need an outpost. However the only outpost to take is one that is already claimed by the dwarves.

Now I've not been able to test if my level 5 heroes can actually outdamage the selfhealing of the building, but that's not even the main issue. There's a large enemy army here of at least 40 units that replenish faster than I can chip away at. So this whole part is pointless. I cannot build my tunnel exit here because I cannot take the base with level 5 heroes with crap equipment. Either it's bugged and that army isn't supposed to be there or this wasn't tested at all. Shame. I guess I'll have to murder all the dwarves on the map now and push through burte force. Pffft.

[Razer]

Ok, seems you can build an exit anywhere, but you need to click on the tunnel entrance and then select build tunnel exit, which can be placed anywhere. Wasn't very clear. Kind of just stumbled onto that.