“Sorry, I’ve just been going door-to-door. Do you, like, got any errands you need run, or...”
“I figured if I was given a reason to run around the city, I’d learn my way around it a whole lot quicker..” And mostly, he’s asking because he needs something to do. Desperately. He’s already spent far too long in his bedroom, not doing anything, not meeting people, not learning more about his situation...until finally he got sick of nothing, of himself for indulging in it.
He could have started by asking this very question to his roommates, but he didn’t want either of them to get too comfortable with the idea of him doing their chores for absolutely no reason, so he opted for visiting entirely random houses instead. At least if things turned sour, he didn’t have to worry about them EVER again. You know, as long as he doesn’t run into them in public! Haha!