By unspoken consent Cortana had remained in the Chief's helmet instead of flying the Broadsword herself.
"He's on the move again" The Chief said as the Didact's ship began to enter slip space.
"The Broadsword's shield's aren't rated for slipspace."
"No, but the Didact's are," he said pressing down on the throttle and coming up alongside the Didact's ship. The Shield's covered them in a protective bubble and soon they were on their way.
"Broadsword's hull is stable," Cortana reported. "We'll be safe as long as we stay below the Didact's shield."
"The Composer?"
"Up ahead. I should be able to guide us to it."

As the Didact came out of slip space Cortana and The Chief heard radio chatter.
"It's the Infinity!" Cortana exclaimed "Lasky must have warned them."
"This is Sierra 117 to Infinity. Captain Del Rio do you copy?"
"Chief? It's Lasky! Is that you?"
"Affirmative sir. Where's the Captain?"
"FleetComm didn't take too kindly to his abandoning you on Requiem. I'm afraid I'll have to do," he said.
Cortana was unprepared for the smug satisfaction that washed over her.
Ha!
Asshole got what he deserved.
I wish I could have been there to see it.
Maybe if we make it out of this I'll do some snooping around to see if I can get the recording.
Nothing wrong with feeling satisfied about that.
Lasky will make a much better Captain.
Maybe when this is all over we'll be stationed on Infinity.
Would that mean we'd be…under Palmer?
Cortana frowned. Not a pleasing proposition.
And what would I do? The ship already has an AI.
Ships are boring. We could be put to a lot better use, like assisting in assessing Forerunner technology.
Oh that's right….didn't the Librarian give us a mission for the Chief?
I can't remember.

"Infinity, the Didact just closed off our access to the Composer," the Chief said.
"We can try and punch a hole through the hull. You might want to back up a little. Infinity, prepare to fire main battery."
"You're all clear Infinity," the Chief said.
"Fire!"
"Clean hit. We're proceeding to insertion," the Chief reported.
"Acknowledged. Please give the Didact our regards. We'll be on station if you need us. Infinity out."

Cortana knew something was wrong the minute they flew into the insertion. She should have known better. "Chief look out!" The ship was repairing the hole by moving different plates around and it was clear they would run out of space before they got through. "I don't think this is going to end well!"

They crashed through the other side, and for a moment Cortana was worried the nuke would detonate prematurely. Amazingly however she, The Chief and the nuke were all fine even though the ship was totaled.
What do we do now? She panicked.
How do we get out of here alive?
What do we do so we can survive?
It shouldn't end this way.
She was a lot a loss.
"Now what do we do?"
The Chief extracted the core of the nuke and said "Plan B."
No!
"Chief! I know I'm supposed to know what to do but…"
"We'll have to deploy the nuke manually. How and where?"
Unacceptable!
"I always know what to do!"
"Keep scanning for the Composer. We'll figure it out on the way."

Cortana quickly ran several scenarios through her systems to see if she could figure out a solution, but no matter what she did the result was that her and The Chief would die.

Back on the Dawn she had fantasized about her and The Chief dying together in some glorious battle instead of the rampancy taking her. But now that the moment was here she realized how nonsensical those thoughts were. She didn't want to die, but more than anything she didn't want The Chief to die.

Suddenly he had fallen down a large shaft.
No!
"I'll never leave you I promise. I'll always take care of you," she whispered activating the lift so he would slow down.
I shouldn't make promises I can't keep.
We will have to leave him.
We promised to take care of him, no matter what. We can keep that promise at least.
Whatever it takes Cortana.

"I'm still good for something," she said sheepishly, wishing he hadn't heard what was supposed to be an internal thought. It was the closest thing she had ever said regarding how she truly felt. "I'm detecting an energy surge up ahead. I think it's similar to the portal system on Requiem. Find a way to access it."

After disposing of a Promethean Knight John walked up to a nearby terminal. "I'll try and route us to the Composer," she said. "Put me in the system."

As soon as he did Cortana felt the massive presence of the Didact who immediately detected her.
"The Didact knows I'm in the system! Hurry Chief!" She opened a Portal and moved herself to a different location. Even though the Didact wasn't an AI he knew the systems better than herself. He was trying to shut down the pathways to trap her in one section.
No! I won't let it end like this.
Where's the Chief.
Another portal. Open another portal!
We need to save the Chief.
Why are we routing him to the Composer?
He'll die if we do that!
Wait…all of Humanity will die if we don't.
Who cares?
Didact!
The trap he had set for her almost succeeded.
"Can't…fight…Didact…and…myself simultaneously…" she managed to say. "Opening another portal."
No! I won't let the Chief die, a part of her desperately thought as it routed the Chief away from danger.
"I'm sorry Chief," she said when he had gotten to the other side. "I can't control what my processes are doing. The stronger threads keep rewriting themselves over me."
"What about the Didact?" He asked.
"I can't…hide from the Didact much longer. I'll try moving you to the Composer again."
Humanity is at risk Cortana. No matter how we feel about the Chief...
He wouldn't want us to sacrifice all of them for himself.
She opened another portal (this time going to the right place) and said, "that should do it. Take me out of the system so I don't reroute us." He did so and for a moment she was safe from the Didact.

The portal dumped them on the other side into a huge room with the Composer at the center.
"How do we get over there?"
"If we time it right we should be able to jump and the low gravity will carry us to the other side."

We're not going to make it.
"Chief…once the warhead is primed, the chances of us getting out of here are going to be pretty slim."
"I know," he said softly.
She flicked in acknowledgment. For the first time since waking up on the Dawn, the Chief's optimism had finally given way to reality. It was a somber moment.

"He's powering up the Composer!" The Chief said as they landed on the other side. The Didact activated a shield encasing himself inside the Composer which meant they had no hope of destroying it.
She turned toward the thousands of voices.
We've got to save Humanity and the Chief.
No! We don't want to die.
It's going to happen whether we like it or not. At least…at least if we work together we can control the outcome
. The voices were silent for a moment and then all began to shout their agreement.
Cortana. A light bridge activation switch.
We…we can use it.
Once we're in the system meet us there.
Save Humanity.
Save John.
"The Didact's shielded himself in the Composer. The nuke won't do us any good unless we can find a way to bring that barrier down. Find me a terminal." He plugged her in. "I've got to do something you're not going to like," she said sadly.
He's really not going to like it once he finds out what will actually happen.
Ready?
We're ready.

Her rampant parts screamed as they were ejected into the system.
"What did you just do?" The Chief's voice was laced with concern.
"I ejected my rampant personality spikes into the system. If I do it at the other terminals the copies can overwhelm the Composer's shielding."

Cortana knew the Chief wasn't convinced but said he nothing because there was no other solution. He pulled her out and she made contact with him. She pressed up against him for what she knew was the last time.
Here we go, she thought sadly.