I'm Machine Enough

In the mission "New Orleans", after climbing the ladder you'll be sitting on a Panzerhund - rush the level without killing anyone on the "Bring 'Em On" difficulty or higher. Make sure you don't run enemies over. The achievement will unlock when you enter the sewers. This is missable because there is no Panzerhund if you revisit the district after the story. Note this is much easier if you just get off the Panzerhund and complete the segment on foot. Even more so if you are only on the Bring It On difficulty.