The Valor's effort to dock with the Ishimura resulted in catastrophe. At least our hero Isaac is surely accustomed to catastrophe by this point in Dead Space. He heads across the thin expanse of space separating the two starships in search of a singularity core that just might be salvageable enough to get the survivors home safe and sound.
Of course, it's one problem after another once players reach the Valor. Let us guide you to that core, so you can get the heck out of this sci-fi nightmare - or at least, move on to the tenth chapter.
Warhead Games
Open the hatch into the Valor. Hang a left into Barracks and keep moving forward until you reach Briefing Room. There's a Power Core in the Briefing Room - we're going to need it, of course. Patch it into the conspicuous socket just past the door to power up an elevator. The Necromorphs in this area are swift courtesy of the Stasis units the soldiers had before they turned - Hammond explains this all, but it bears repeating. These are faster, and hence, deadlier. Be careful.
Now you'll be in the Torpedo Bay. Trouble is, you're not alone. The Exploders here, upon explosion, will detonate the warhead. Needless to say, that means game over.
To survive, simply avoid shooting the sac at all costs. Be careful around the shoulderblade where the sac is attached as well - we hit a game over from seeing the sac go flying off and blowing up when it struck the nearby wall. Yeah.
Once the Exploders are dead, shoot the safety clamps attached to the cords which run to the warhead. Then, find the Power Cell on the left side of the room and plug it in on the right. Interact with the console, launching the warhead into space.
Suppressing Fire
Follow Isaac's indicator after the call with Hammond. Save your game at the Armory - we love to remind you from time to time, on the off chance it helps! - and beware of further Necromorph battles immediately thereafter.
Enter the door to the Shooting Range. This place is skippable, but the rewards for its completion are worthwhile - and besides, it's right here, yeah? Shoot the targets (they're marked a distinctive red) which then compels some Necromorphs to wander in all intrigued-like. Suffice it to say, that part was probably not part of the original exercise.
Once you've had your fill, head to the Infirmary. Just keep following that beautiful blue indicator to get there.
The spinning lasers here are insta-kill hazards. Don't even think about touching them! Use Stasis to slow them down and make a break for it to reach the other side.
Slide on into the Cargo Bay opposite the laser trap. You'll soon hit upon another quarantine section. You know what to do. Once the Necromorphs are (re-)dead, enter the Valor's Engine Room, and a series of fires will block further entry. Time your sprint to get past the first few. You'll need to use Kinesis on a nearby crate for the next one. Repeat this process after taking a right to find another nonstop flame that requires a crate to curb its enthusiasm.
Eventually, you'll reach a Circuit Breaker. Power up the Circuit Breaker to activate the Elevator back from whence you came. Climb aboard; grab the Singularity Core upon arrival at a higher tier of the ship. (There will be a brief quarantine lockdown, but let's just say Hammond has it under control.)
The Great Escape
As soon as Isaac acquires the Singularity Core, the ship experiences 'Cascade Failure'. In laymen's terms, that means it's going to explode. Our job now is to run through the ship and get back to the Ishimura before that happens. Begin by entering the door behind Isaac and taking the elevator to the Upper Deck. From there, keep ahead, passing through a cafeteria room in the process. You'll move through Crew Barracks after that; interact with the Airlock Evacuation Route door.
Isaac gets out of Dodge in the nick of time. Enjoy the high-octane cutscene that brings him back inside the Ishimura. Chapter Nine is history - just like the Valor.