My kingdom is walled off everywhere except one small area that is the only place enemies can enter my kingdom. There is a series of doors that slow enemies a lot and I recently built a "watchtower" of sorts to snipe from. I want to trap the goblins there with a block of dirt so that I can make sure my sniper squad actually do their job from the tower, but no matter what I try, anytime a gnome sees the goblin horde, they will rush in and fight (and die), or run in fear without completing the build. Is there any configuration that might work? or should I just have the wall up before the goblins arrive?