The hardest part of this "DLC," is figuring how to get out of the room you start in. You need to power up three electric conduits. You have to power up the one on the other side of the wall right as you start, then turn to your right and power up that one then the one above the door you start at. Do this and a shield will roll back allowing you to break though the glass. After this, there's only about 5-10 minutes of gameplay (depending on how good you are at stealth) separating you from this achievement.