To clear a room without a door, first toss a phosphorous grenade in. Then, have Jones follow you and have Foley and Connors cover the entrance. Next, tell Jones to rush the opposite side of the room. Also move in at the same time and rush a corner, gunning down any resistance. If there is a door, then position someone with an automatic weapon facing the door (preferably Connors), then open the door and back off while Connors polishes off any resistance. Finally, rush the room and tell Connors to follow you and shoot anything that moves.