First of all, absolutely loving this game. I've found it really easy to pick up and its so much better, in my opinion, than other games of it's type such as Kingdoms and Lords and Total Conquest. I have a quick wisdom thought which fellow players can hopefully answer...
If you build a wall around a defense bunker, when being attacked can your own troops get out of the wall to defend?
If you build a wall around a defense bunker, when being attacked can your own troops get out of the wall to defend?