The final chapter begins immediately after you grab the shockpoint drive from the mid section of the ship. Isaac and Carver begin to argue about what to do with the drive. Head back the way you came and take the elevator back down to the lower corridors. Have your weapon at the ready as you backtrack toward the tram because several doors have cultists waiting for you on the other side.
When you make it back to the room with the small cargo elevator, step back after calling it down as when it reaches the bottom, a hallucination of Carr will appear right on the platform and assault you.
After a few threatening words, things will return back to normal. Or at least normal for Isaac. In the next hallway, Carver will contact and try to reason with Isaac again. Pass through and into one of the small rooms. As soon as you try to open the door, the world will turn red and you will have several cultists to contend with.
The rest of the trip back to the elevator is enemy free though not hallucination free. Take the elevator back down to the tram and take it to the aft deck. When you reach the far side, follow the objective marker through the open door into a small room with some scattered supplies and a torque bar door.
Gather up what you want then open the other door in this room to move on.
WEAPON PART + CIRCUIT
The door that requires a torque bar contains an assortment of parts and supplies as well as a MK-II Diffraction Torus and a +3 Rate of fire, +3 Clip circuit on the shelves.
This next room has a workbench tucked in the corner to the right of the steps. Take a moment to install any new components you may have grabbed then head up the steps to continue toward the engineering bay.
Carver has locked the door and you have to fight to get past him and blow up the ship! After the lights flicker, Carver will take up a position on the upper areas of the room. He is easy to spot because of the red glow of his visor. Be careful to stay ducked down as much as you can or he will train his laser sight on you and start firing his assault rifle.
Wait for him to reload and when he peeks back out of his cover, hit him with stasis to buy yourself the time to shoot at him. After a few shots, Carver will vanish and you realize that all is not as it seems. Isaac's vision will turn red as he slips into another hallucination and multiple copies of Carver will begin assaulting you from different directions.
Take an aggressive approach and kill off the hallucinations as quick as you can to minimize the amount of damage you take. They disappear after only a couple of shots so don't worry about using your stasis for now. Eventually you will be transported again to Carr's world. This time however, there are three markers!
Use the same strategy as before, avoiding Carr and his necromorph minions, which now includes wasters, while you wait for one of the markers to glow yellow. After you destroy a marker, Carr will become stunned and drop to his knees.
This is your opportunity to unload everything you have at him. You only have a short time to damage him and if you don't hurt him enough in time, the marker will regenerate so ignore the necromorphs in favor of shooting at Carr. Once you deal enough damage, he will release a pulse of energy and disappear. After a quick breather, Carr will reappear and summon more necromorphs. Continue fighting and destroy the final two markers to be released from the nightmare. Once you regain your bearings, you will see Carr grovelling on the ground talking to himself.
You can either stomp him and put him down or just ignore and spare him. After you've made your decision, follow the objective marker and take the elevator down to the reactor. When you enter the reactor chamber, head to the left and activate the panel to set the reactor spinning.
This also disables the gravity and allows necromorph medusas to begin floating in the chamber. Along the back wall are three fuel orb chambers marked with yellow panels.
The closest one's lights turn from red to blue when once the reactor starts spinning. Use kinesis on the lower part of the panel to spin the crank and release a fuel orb.
The goal is to get the orb into one of the glowing openings in the spinning reactor and to accomplish this, you must first use stasis to slow the reactor down. Now use kinesis to grab the floating orb and launch it into one of the openings.
The reactor will become overheated and try to vent by raising three yellow cooling cylinders from the base of the generator. Shoot them one by one as fast as you can to stop the venting.
Repeat this two more times to fully charge the reactor. Head toward the exit and be prepared to be launched into space. The force of the ejection and Isaac's thrusters send him careening back toward the mid deck of the ship. Dodge the jets of flame being expelled from the damaged ship and shoot the mines before they reach you to arrive back on the mid deck in one piece.
Check your objective marker to get your bearings then head to the cockpit where Isaac and Carver will set a course for Earth and finally arrive home...