Start a terrorist hunt with the least number of terrorists on kill house.

First run up the stairs to the corner of the long cat walk, kill the 3 terrorists who rappel down the rope, then the terrorists who run from the middle of the cat walk.

Then throw your grenades over the roof, aiming them to the rappel at the front of the building, this usually kills 8 terrorists in one go and has helped me reach level 100 assault.