This is a story related achievement and cant be missed. This is for beating the boss i Chapter 10. It is a big mofo that throws cars at you and breaks your cover so you are never safe. You will want to shoot at the heads until it reveal it's "eye". You will know it once you see it. Once revealed light it up.
There are two rooms you can hide in and grab items. Do not stay there long. The monster will attempt to grab you(Use this time to fire at it. It will back off. At this point run out. If you stay it will grab you on the second attempt and smash you through the wall. It isnt fatal(regular game modes) but it will do damage.