Set up a realistic terrorist hunt on Kill House, with lone wolf disabled and density set to low.
Make your way to the roof as soon as possible, and keep moving around so as not to become an easy target. A considerable amount of the terrorists should make their way towards you, most of which will rappel up the side of the wall, making them easy targets. Your team mates should pick of many of them.
Just use your guns and grenades to kill as many as you can, while doing loops around the roof to ensure you do not have your back to a possible entry point for too long.
When you have killed most of the terrorists, and it looks as if no more are coming towards you, take the stairwell from the roof and proceed to clear out the two floors below, usually where the remaining terrorists will be. Send your AI team in first to attract fire, and wipe out the remaining terrorists.