I'd like to add to Eldres AUT's and Bigjimboski80's time saving solutions with a huge time saver. When reaching the objective at the building in front of the square, you do not need to enter the building and fight all of the enemies on every floor to to reach the general or whatever rank he is to complete the objective. Instead, just clear the front area in front of the entrance doors and pick up the remote helicopter on the left side of the entrance and go crouch further in that same corner as to be safely hidden from fire and launch the helicopter strait up facing the building. Keep going strait up until you see the objective target on the guy you need to kill through a set of windows that are OPEN. He is the only person you need to kill in the building. You can kill him with the helicopter from outside and the objective condition will be complete for the area. Hope this helps save some frustration and time for people.