There aren't many quicker ways into Cortana's good graces than to tell her she's great, even though Locus is kind of bloodless about it. It's that bloodlessness that makes her pause before answering with her usual flippant comment that yes, she is that good, thanks for noticing. She's used to unyielding Spartan self-discipline. This is something else, something she's not sure she's got the shape of. Why is 'decide' and not 'fight' the important word? Most humans don't give choice a second thought.

Cortana will abandon the Master Chief the day she stops functioning, and he'll never walk away from a fight. But...what if she had come from before they'd met? The Time Trapper could span four years; seven would be no effort, presumably. What if she'd still been Dr. Halsey's personal AI, the Mjonlir Mark V that could hold her not yet come to fruition, and had been offered the same choice? Live out your days in comfort, as a full citizen, surrounded by other intelligences like your own for the first time in your life...or fight a hopeless war against an implacable enemy?

"Civilian life wouldn't suit me, either."