The lights are on
Ok, in the map Vallhalla, there are the two towers. If you are playing offline multiplayer in forge, go into the bot and fly up as far as you can, then you can go to either one of the towers. When you get to one of the towers, un-bot yourself and start getting some headshots. In online multiplayer, not in forge, you can use a banshee to get to the top of the towers. Use the same technique.