Someone made the huge mistake of introducing me to the Halo series with Halo 4 for Christmas. Needless to say, I'm a CortanaChief shipper.
He just finished putting a bullet into the last Promethean Knight's body and while it fell he heard her over his comm.
His head tilted barely up to signify he was listening while he briefly searched the area in case there was an enemy in hiding before they moved on. Satisfied, he reloaded his rifle and continued through, slower this time to give Cortana time she needed to speak.
"I love you."
Master Chief's footsteps paused for a second. He hadn't been expecting that... but he wasn't surprised by it either. The corners of his lips lifted into a small smile at her avatar window on his visor.
"Good." she nodded back to him. By the tone of her voice, it seemed Cortana thought that was the end of the conversation. It probably should have been, but...
"I love you too."
She offered a small laugh, the sound of which he hadn't heard in a while and he found himself brightening at it.
"I know." she told him, perhaps meaning to repeat his own same reply. Of course she knew he loved her; of course he knew she loved him. They had come across this realization a long time ago. But in the isolation of their current situation, with no one to watch or judge for just the moment, it seemed they both deemed it acceptable to say aloud what they felt while they had the chance.
To be honest, it felt pretty good.
"Good." he replied, and he raised the Assault Rifle in his hands and shot the Promethean sentry that had entered his sight.