"Oh, the social butterfly," Cortana says dryly. "I've worked with worse." That part's not a deadpan joke--ONI AIs have terrible people skills. (What that says about Cortana is left as an exercise for the reader.)

"He might not be in great shape if we do find him," she cautions. "Our host doesn't have our best interests at heart." This all echoes the Flood much too strongly for Cortana not to jump to conclusions regarding assimilation. Those whispers in the darkness offering her eternity can't all be the hallucinations of a digital mind teetering on the brink of rampancy; even if Brainiac's promised cure hasn't worked, nothing has pushed her far enough to break. Not yet.