As they are still in transit, Cortana explains what she's found.

Cortana: The Covenant network is in absolute chaos! From what I've been able to piece together, their leadership ordered all ships to abandon Halo when they found the Flood, but they were too late. The Flood overwhelmed this cruiser and disabled it. The Covenant are terrified the Flood will repair the ship and use it to escape from Halo. They've sent in a strike team to neutralize the Flood and repair the ship for immediate departure. I've got a good lock on Captain Keyes' CNI transponder signal! He's alive! And the implants are intact! There's some interference from the cruiser's damaged reactor. I'll bring us in as close as I can.

Chief and Y/n teleport into the end of a corridor in the cruiser. They look up and see they'd teleported to the ceiling before dropping down to the floor, both groaning.

Cortana: Ohh... now I see, the coordinate data needs to be—

Chief whacks the side of his head with his fist as he stands up.

Y/n: (pops his back in place) Was just about to suggest you do that.

Cortana: Right. Sorry.

The pair start making their way through ship until a voice comes on the COM.

Captain Keyes: (COM) Chief, L/n... don't be fools...leave me...

Cortana: Captain? Captain?! I've lost him...

Y/n: Maybe they took him to the prison cells, like last time?

Cortana: His life signs were coming from the bridge.

Chief: Then let's go, L/n.

As they continue through the ship, they see damaged bulkheads and destroyed doors.

Cortana: The damage caused by the crash and the Flood have sealed-off all nearby access ways to the control room. We should find another way in.

They then get to a hangar, with a large hole in the floor just past the door, blocking your progress.

Y/n: What the hell did this?

Cortana: Analyzing damage... This hole was caused by some kind of explosive. Very powerful if it tore through a ship's hull. All I detect down there are pools of coolant. We should continue our search somewhere else.

Flood began dropping out of a hole in the ceiling behind them, cutting them off.

Cortana: Warning! Threat level increasing!

Y/n: I think we got that!

The Flood start pushing them back towards the hole.

Cortana: That jump into the coolant is looking better all the time!

Y/n: No way am I jumping in there! Not happening!

More Flood arrive.

Cortana: Trust me! It's deep enough to cushion our fall!

Y/n: For the love of God, no! Just keep shooting!

Cortana: We need to jump now!

Flood continue to pour out the hole, and from down the hallway, seemingly never ending.

Y/n: Cortana, if I die from this, I swear I'm gonna haunt your holographic ass!

Chief and Y/n then jump, Y/n yells as they fall into the coolant pool and crawl out.

Chief: You good, L/n?

Y/n: (shudders) Yeah. Let's just, (wipes coolant off his visor) let's just keep moving.

Cortana: We need to find another way back aboard the ship.

They check their weapons and start heading back towards the ship.

Cortana: We should head this way, towards the ship's gravity lift.The crash did more damage than I suspected. Analyzing. Coolant leakage rate is significant. The ship's reactor should already have gone critical.

Y/n: Please keep comments like that to yourself, ma'am.

Cortana: Power source detected. There's the gravity lift. It's still operational! That's our way back in!

Chief and Y/n jump into the lift, shooting upward back into the ship.

Cortana: We should be able to get into the ship's control room from here.

They then continue on.

Cortana: The Covenant Battlenet is a mess. I can't access the ship's schematics. My records indicate that a shuttle bay should be... here.

Cortana marks the spot with a nav point. They then enter and stay quiet as they see Flood.

Cortana: Look, in the corners. The Flood are gathering bodies here.

Y/n: I don't intend to be added that collection down there, Chief. Let's find the Captain and get out of here.

They then enter another shuttle bay.

Cortana: Looks like another shuttle bay. We should be able to reach the control room from the third level.

Captain Keyes: (COM) I... gave you an order, soldiers! Now pull out!

Cortana: He's delirious! In pain! We have to find him!

They then make it to the third level.

Cortana: The control room should be... this way.

They then hear Keyes scream in agony on the COM.

Cortana: The Captain! His vitals are fading! Hurry!

Chief and Y/n double-time it to the bridge and see some kind of large sack.

Cortana: (horrified) No human life-signs detected. The Captain! He's one of... them.

Y/n: (holds his stomach) I think I'm gonna hurl.

Cortana: We can't let the Flood get off this ring! You know what he'd expect... (quietly) What he'd want us to do.

Y/n: You do what you have to, Chief. I can't watch...

Chief punches into Keyes' skull, sticking his hand inside. He pulls out the neural implants, shakes the Flood biomass off of them, and inserts them into his helmet.

Cortana: (quietly) It's done, I have the code. We should go.

As they exit the bridge, Y/n stops and leans against the wall for support as his legs started to buckle.

Chief: L/n, we nee to go.

Y/n: I don't think I can do this anymore, Chief. All the death, all the corruption, all of this.... we might be the only two humans left on this ring.

Chief: L/n...

Y/n: (exasperated) You have to go on without me. I can't do this. I just can't....

Chief kneels down to Y/n.

Chief: Y/n, listen to me.

Y/n looked up, surprised that the Spartan called him by his first name.

Chief: I know you're scared. And I know that you wish you turn off your fear instantaneously, but we need to go on. Not just for the Captain, but for all the Marines that died on this ring. If we don't stop the Covenant and the Flood, Earth will be at risk.

Y/n: Earth...

Chief: Exactly. No matter what, I have your back. And I know you've got mine.

Chief stands and extends his hand to him. Y/n looks at it before taking his hand and standing.

Y/n: Let's get it done.

Cortana: We need to get back to the Pillar of Autumn. Let's go back to the shuttle bay and find a ride.

Once they reach the shuttle bay, a Covenant dropship enters the hangar, dropping off more troops, escorted by two Banshees.

Cortana: Perfect. Grab those Banshees, and we'll use it to return to the Pillar of Autumn.

After taking care of the Covenant, Chief and Y/n hop in the Banshees and fly out with plasma bolts being shots at them. They then fly towards the Pillar of Autumn, hoping to end this nightmare once and for all.

(THE LAST CHAPTER OF COMBAT EVOLVED AWAITS! ALSO ONCE I'M DONE, I'LL EXPLAIN HOW Y/N WILL BE IN 2 AND ODST!)