Arlo spotted Sophie and blanched slightly. That was a kick in the balls. She was just a kid. Arlo was not cool with kids being here. Made him think about Laurel - how half of him wanted her home safe and half of him wanted her here with him, because he missed her like hell.
But this girl looked scared. And she didn't seem to know anyone. New arrival? He walked a little closer to her and crouched beside her.
"You new, kid? You get here with anyone else?" - standard question for all new arrivals. Flash of hope and fear in the dark - "You looked scared as hell." He was trying to sound nice, but the whole grizzled hobo appearance and general sulleness of Arlo Thayer probably didn't pull it off all that well. Also, if the girl admitted she was freaked and started crying or some shit he didn't really know what he'd do. He scowled to himself and gave himself a mental chiding for trying to get involved. What the fuck did it matter? He was leaving. Asap.