I've got a thought for you, if you're interested: I wrote into my app for Dust that he'd been conscripted into a couple of extractions shortly after his own to save people who otherwise would have been killed. The timeframe is right, the TLOU Matrix is definitely a dangerous one for operatives, maybe Ellie was one of them?

Either way, Dust is the sort of person who functions a lot better if he has someone to banter with and trade lighthearted jibes.