Dead Space 3 walkthrough, Part Eighteen: The Drill
The Unitologists are back with a vengeance, and Isaac is no happier to see them now than he was in friendlier space. Their leader, Danik, still wants our poor hero dead - though he can't find Isaac if he goes underground. Right? Right. Coring Platform it is.
You'll come out in a large, open, icy area which was probably used for drilling (duh). Check to the immediate right of the elevator for a wall container with an Upgrade Circuit, and the boxes in the back for a Telemetry Spike. Get the generator here working and you'll not only activate a Bench, you'll open the way to the massive drill in the center of the chamber - a drill that's obstructed by… something. Hrm. Open the safety gates to try to get it running properly.
Naturally, it will not run properly. Prepare for the oddest boss fight in Dead Space history as you take on a giant drill!
This is a three-stage battle. When the drill starts up it will attract the attention of Necromorphs who, despite the danger, still want a piece of you. You need to take them out as they come towards you (or lure them into the drill as it spins around the small arena) then use Stasis to slow the drill. Once the blades stop whirling, fire at the yellow core inside several times. The drill will respond by opening a little more, making it harder to get away - though you must, as being touched by the drill is a one-hit kill. The second round is no different than the first, though there are more Necromorphs to plow down. Use the various Stasis Recharge stations positioned around the arena to maintain your energy stores.
This battle gets worse at its third stage. The drill isn't much more dangerous on its own, but the Necromorphs that start to appear are of the skinny, swift kind. They're easy to kill, but there are so many that it's easy to lose track of the giant piece of machinery. Rather than focusing on killing the Necromorphs, put a huge heap of them in Stasis and turn to fire at the drill. The blades should be so far apart that you won't have to put it in Stasis to aim properly. Peg it five or six times and it will rip itself apart, ending the battle… and making all of the Necromorphs vanish. Who cares how?

Pick up the swag left over from all the Necromorphs that got killed during the fight (there will be a TON, assuming you haven't been picking it up already) and enter the elevator the drill was blocking. Past another lift you'll come up outside a new structure, ominously labelled the NX-03 Site. Check behind a girder opposite the lift for an S.C.A.F. Artifact and enter the site elevator.
At the top is… a giant… thing. Ellie explains what she thinks it is, calling it the Nexus, and everyone decides that they have to thaw it so they can get inside. Lovely. Isaac volunteers, because, frankly, no one else ever does anything around here. Use the Bench beside the elevator if necessary, smash containers for items, and run down the walkway to the Furnace Room at the end. Time to unfreeze an unfathomable horror from beyond the stars!