Currently? The wall dissapears but the black region remains uncrossable.
My thinking though would be that cliff explosives should blast a tunnel and new cliffs would be added around the blast site. So you could make a break in the wall and create extra loops but not get onto the wall itself. Haven't looked into how to catch cliff explosives being used in LUA or if you reasonably can at all. Worst case cliff explosives need to be removed from the game. Maybe have a tunnel borer entity instead that bore a tunnel through a wall over time. Similar to the terraformer entity now.