The REAL easy way to get this achievement (if you are connected to Xbox Live, thanks ego orb) is by going to Multiplayer >> Custom Match, then selecting Drowning Doom and starting a match without any other players or AI. Capture the fan-geysers and do not attack the empty enemy stage. Upgrade your stage. Produce units. Double-team with your units. That's a bingo!
Shouldn't take too long and it's easier than the other solution posted here because you don't need to have a friend with you.