Dead In Their Tracks!
Get a quad-kill while defending an objective.
Acquirable through the Solo/Co-op mode of Conquest if you haven’t already unlocked it through Multiplayer. Launch a game with the map set to Orbital and AI difficulty set to beginner. As you spawn, get yourself into a tank and drive towards objective B2 as it has great surrounding visibility. Once there, capture the objective and wait for enemies to show up in vehicles. Heavier vehicles tend to have 4 BOTs in them, whereas lighter vehicles may only have 3. If lucky, you may get it on your first try; if not, just sit around there for a while, and you should have the achievement soon enough.