In local co-op, play the Nightclub Chapter. (2 Controller needed)
Then play as Lynch (The Lynch Account gets the Achievement)
Now kill with Kane all the Guards and mad Guys and after you have done this, just walk with you Main Account to the end of the Level :)
You can do this on Apirin difficult,another nice effect of co-op is,you can control what your "teammate" is doing.No Stupid dying.