They're under a ruined overpass when he spots it, next to a quietly burbling stream.
"Hey, 2B, look at that."
"Do you do stuff that's not fighting machines? How'd that happen, that you were made by moon humans and never saw the moon?"
"Not really, actually. Fighting machines the whole point of us. There are automated factories in orbit."
"What happens to you then? What's the average time on the 'until you break down'? D'you still break down if you don't get shot or something? Do repairs not help?"
"Parts wear out over time. If you get them replaced or have a back up, you're okay. I don't think any YoRHa unit has reached a natural end to operational life yet."