Barrow knows instinctively that he's done wrong at this point, and his natural joviality has melted away into an awkward hunch as he focuses almost exclusively on his cigarette. It's not that he's insensitive, he'd tell anyone who asked, it's that he knows when to choose his battles (and the answer is usually Never, Unless A Sword Is Needed).

He doesn't challenge her, and perhaps doesn't even disagree. But he doesn't say anything either, no doubt hoping she'll drop it and go away so he doesn't have to make a break for it.