If you haven't learned from Dead Space 1, (or from the tip during the loading screen in DS2,) it's always a good idea to carry a spare power node on you at all times. Though usually random, unlocking rooms using them the majority of the time reward you quite well.
That being said, make sure you have a power node on hand during Chapter 11. About midway through the level the main walkway will "T" off and on the right you'll see a locked room that you'll need a power node to unlock.
In this room you'll find random loot as well as the schematic for the Advanced Suit. If you're still unclear where the room is,
The achievement will unlock after you purchase it from the next store you get to for 40,000 credits.
Still can't find it? Here's a video guide supplied by Reabo: