Army of Two (EU)

There's not a great deal I can offer you in terms of how to get this achievement, it's all in the description, complete the sixth mission of the game on Contractor difficulty or higher, however you may find these videos of the sixth level handy, it'll help you get your bearings on any part you might be stuck on and give you an idea of what to expect!

*^{Credit to viconaz and LikeYOURMOM for the videos}

Just be sure, that you are on the top floor where Clyde is. When you stay behind the turret downstairs you dont get achievement.