On Kikowani Station, right at the beginning, just run past all the enemies and jump into a Banshee. Proceed to splatter 7 of the nearby enemies you ran past (grabbing a health pack near the start of the mission if need be) to unlock this. This isn't cumulative from what I can tell, so you'll need to get 7 splatters without dying.
I've included a video below with loads of achievements. For the Fast and Low achievement, start at 22:00