While I would like a indoor only map, for a change of pace, I don't see how a battle could be fought inside a building only. Maybe 2 or 3 buildings but not just 1. How about there are 3 buildings and the middle one has all the objectives in it (meaning you spawn in 1 of the side buildings until all the objectives are capped in the middle building and then you spawn outside and have to hold your former spawn). Of course going outside to sneak around to a unused entrance would be dangerous, being as your in plain sight of the enemy spawn. The middle building would have to be big though, so the map wouldn't be very wide, just really tall.