Play this level on EASO (Easy All Skulls On) except Blind Skull. Do an assassination kill as many as you can while getting rid of any Elites and Grunts that do not use Concussion Rifle and Energy Sword. There are only two weapons the player must equip once there are no more Elites and Grunts that does not equip Concussion Rifle and Energy Sword. Keep your Concussion Rifle at your disposal to clear out any scattered Plasma Grenades while use the Energy Sword to replenish your shield and if possible, assassinations.
Note that this can takes up to 1 hour to use this method considering EASO except blind skull is the safest way to reach 150k points.