You can get this by making purchases on vending machines during escalation matches purchasing ammo, overshields, weapons and health count towards this. also opening doors count for this.(there is a progress indicator that will pop up on the bottom every once in a while to help you keep track)
This is a progressive achievement so it does not have to be done on one playthru it took me 6 escalation matches to get it but i guess that will depend on how well you play and how good is your team but you will eventually get it.
the best way to rack up score is in the autobot escalation taking out jets since they dont need much damage and they give you 75 points every time, if you feel you dont have anything to spend your points talk with your team and buy them overshields, ammo or whatever they need so the game can continue and you can keep racking up those points