Major spoilers for episode 7 of Spartan Ops, takes place directly after the episode. References the Halsey easter egg in the "Requiem" level.
I took Halsey's reaction that she didn't even know that John had been found, so I'm assuming that she thought John and Cortana were still floating in space until Roland spilled the beans.
This isn't the first time Catherine's life has been in danger.
Over the course of the War, she found herself in many precarious situations. Elites shooting at her as Kelly and John rescued her, escaping through the underground network of tunnels on Reach as Jun sacrificed himself so she could survive.
But now, as she is standing behind Lasky with a Knight just a few meters away, without a Spartan standing between her and death, she is hard pressed to recall a time when she has felt so vulnerable.
The captain fires another round in the Promethean's direction. It begins to glow orange and Catherine knows the shot is fatal. Before it can completely dissolve, Lasky grabs Catherine by the arm and leads her down a hall. Halfway down the corridor, he shoves her through a door that opens to a small conference room. Two soldiers slip in behind him before it slides shut.
Lasky is at the door's controls, locking them, but Catherine knows that their escape is temporary. There is no safe haven on the Infinity.
"I need to get to John," she demands, keeping her voice even. Yes, she is scared, but if she can be reunited with Cortana, they can solve the mystery of the Librarian before Jul 'Mdama. "Cortana will-"
A look of awkwardness passes over Lasky's face as he looks at her. "Cortana's program terminated six months ago, Doctor."
Catherine staggers backwards, her fingers loosen around the datapad in her hand.
No. Cortana wasn't supposed to succumb to the madness of the AIs that had come before her. Catherine had studied the research herself. The recessive variant she found in Cortana's seed programming was supposed to have prevented her from rampancy.
"Due to rampancy?" The last word sticks in the back of her throat.
Will it hurt, Doctor? When I go rampant? Cortana had asked her one afternoon in her lab on Reach.
Catherine had dismissed the AI's concerns immediately; there would be time to research and develop a theory that explained the rogue element in her core processes. They would be able to find a solution to her rampancy, she had told herself.
But then, Operation: RED FLAG had been authorized and all further research of Cortana's unusual programming had ceased.
There is a heavy silence that settles over the room. The soldiers shift their gaze from Catherine, moving to the door. They knew what happened to the AI, she realized.
Did everyone on the ship know about John and Cortana's fate except for her?
"That's classified," Lasky finally answers.
The sound of gunfire is growing closer, but Catherine doesn't care. She moves to stand in front of him. His cheek is still slightly pink from where she slapped him.
"You would keep more information from me?" She takes a step closer to him. He tenses, but doesn't back away. "Cortana is-was mine. Tell me what happened to her," Catherine hisses.
Lasky's eyes move downward. He sees the windows on the display of the tablet and knows the information they contain. The image of John's armor is impossible to miss. "I can't, but you already have everything you need to know." He hesitates briefly. "Where do your loyalties lie, Doctor?"
There is an element of fear behind his voice. As if he is truly scared that she will turn her back on the UNSC. If it was not for the billions of people the Covenant slaughtered, she might be tempted to defect. But, she knows that, despite the politics of the UNSC, she will do anything to save humanity.
She straightened and meets his nervous look unwaveringly. "With those whose trust is warranted."
He relaxes slightly. "The Master Chief."
She gives a curt nod. Perhaps Lasky is more observant that she assumed. "John would not keep vital information from me, Captain. He understands the importance of a successful mission. Especially when it involves someone as significant as the Librarian."
An explosion outside the door shakes the floor beneath them. Roland appears on a plinth in the corner of the small room. "We're getting overrun, Captain. Commander Palmer and her Spartans are doing their best, but I don't know how long before the Knights overtake the Infinity."
Lasky looks at Catherine, then back to Roland. "Upload Sierra-117's coordinates to the Pelican that has the data you transferred earlier." He looks at the two soldiers standing there. "You two, get Doctor Halsey to the transport."
The men hesitated briefly, but utter a reluctant, "Yes, sir."
Roland is not so quiet on the subject. "You're going to let her go? After what she did to me?" he sputters.
Lasky tenses. "I have to do whatever it takes to protect Infinity, Roland. If she can get to the Master Chief's position then she might be able to figure out a way to get these Prometheans off the ship."
"I don't know if it's wise to put your faith in her, sir," Roland says frankly.
Catherine takes no offense to the AI's words. "You asked me why I did it. Why I took the risk that I did?" She looked down at the tablet in her hand. "Because, rules and regulations, are for children who don't know any better. Instead of embracing the secrets the universe has to offer and using that to better humanity, the bureaucracy of the UNSC strangles us."
She meets Roland's distrusting look. "The universe is a dangerous place to live; not because of the creatures who are evil, but because of the people who won't do anything about it."
"Misquoting Einstein isn't going to change my opinion of you, Doc. Not after everything you've done to me," Roland replies. "Still, I know how to follow orders." He lets out a sigh. "The Pelican is ready."
Catherine turns to the captain. "You risk losing your command, you do realize that, don't you?"
"If I can save my crew, then it's worth it." He raises the gun in his hand, readying himself for the fight that lays beyond the door.
She gives a curt nod as he taps a command into the panel, allowing the door to slide open. Chaos fills the halls. More soldiers are there, taking cover behind beams and fallen debris. She is unable to see where Lasky runs off to; her armed escorts are pushing her down the hall, being her human shield.
Catherine forces herself to ignore the fallen bodies that they pass. More than once, she wishes that she had a firearm herself; she is far from the helpless damsel in distress.
They dodge another barrage of bullets that come their way. When they reach the end of the corridor, a door to a lift is waiting.
"This will take you directly to the Pelican bay," one of the soldiers say. "We'll make sure the Knights don't get through, Doctor."
She briefly wonders what is the likelihood they would survive with no armor to protect themselves from the powerful Prometheans before pushing the thought aside. She needs to get to John.
Catherine steps on the lift. The ride is quiet, though she can almost convince herself she can hear the sounds of explosions around her.
When the doors open, she half-expects to see a group of Knights ahead of her, but the bay is empty.
"It's the one in the far corner," Roland's voice cuts over the comm channel tied to her datapad. "And though I still think your actions are reprehensible...good luck, Doc."
She doesn't reply. If he is looking for some kind of remorse on her part, he is foolish. Without her overriding Roland's program, she would have never known about John.
Or Cortana.
Catherine can't think of her. Not yet.
She strides purposively to the Pelican and takes a seat in the cabin's chair. The transport begins to move, autopilot taking over.
She waits until she is out in the openness of space to open another comm channel. Her fingers are slightly trembling when she reaches for her tablet.
She never allowed herself the luxury of believing that she would ever see him again.
With a wave of annoyance, she steadies her hand. Now is not the time to get emotional. She presses the button. "This is Doctor Halsey. John, can you hear me?"
There is a long pause. Then, a voice she hadn't heard in nearly five years responds, "Ma'am?"
She wonders if he knew she was aboard the Infinity or if Lasky had kept that information from the Spartan. "There is a situation on the Infinity. I'm coming to your position now."
"I'll be ready, ma'am."