"Last time I had some mobility issues." She wouldn't have gotten far against the Gravemind's omnipresent tentacles and armies of combat forms regardless, but Cortana would really prefer not to be thinking about all the different terrible ways their final battle of wills could have ended. Unfortunately, that flawless AI recall of hers is currently doing the opposite of helping, and the Gravemind's voice echoes faintly through her memories.

This is not your grave, but you are welcome in it.

"Let's find that friend of yours." Maybe Sombra heard it and maybe she didn't, but standing around talking about the Flood won't get them out of here any faster. "What's their code name?"