During the second DLC mission you are in a tank for the entire duration. It is a bit awkward to control but just keep chugging along blowin' shit up and rolling through whatever gets in your way.
About halfway through the mission, Winters will yell over the intercom that some boys in the Red Faction need some help. It's not out of your way and I believe it's actually impossible to miss this trophy. As soon as you eliminate the enemies in that area and then blow up the force field generator, you will unlock this trophy.