I just got the achievement and this is what i found to be most rewarding
Mode: Total Chaos
Map: Complex
Weapon: Nano Rifle (trust me)
Backpack: Tremor
Building Collapse : High (I never experimented with low though...)
Barrels:On
For anyone wondering "Why Nano Rifle?" its just my experiments. The highest I ever got using Thermo was 160k, The second round of nano i got 187k (highest ever being 190k). Any decent nano round usually scores around 150k and up.
So this is how I use it.
The time got my highest score i ran corner to corner diagonally though the building firing off my rifle with the tremor pack active. The Tremors cause almost all the barrels to explode taking down most of the support. For the building with the smoke stack divert your path a bit so your tremors will affect the few barrels around the base of the smoke stack to destroy it.After you've ran through the 4 buildings look back and any stable ones blast at with your rifle. About dying, you may die a few times doing this with all the barrels exploding and building falling on your head, but this really doesn't affect your score at all, you should still have time to take down all 4 buildings as long as when you start you destroy one of the buildings closest to you and keep moving forward (so if you die you start with the other building next to your spawn). Whenever you die you will respawn in your original spawning point.
This achievement isnt hard or take to much time, it just can be boring. Just do 1 match of 4 player - 5 rounds to win every day and you should be done in 3-4 days