To get this achievement, you complete the prologue chapter. The chapter consists of you following Anya after you get out of your jail cell and fight a bunch of grubs. You get infinite ammo and can't die if you take cover. The chapter will then end when Marcus wakes up.
This is also the first achievement you get during campaign and it takes less than 5 minutes.
IMPORTANT - There is a collectable in this chapter. It is in one of the cells to your right when you get out of yours. Just kick the door open and it'll be right there.