He doesn't know. Just like Natasha didn't know before she asked, he has no idea why that question hurts. The attempt to keep quiet is a brief thing, plays out across her face in a fairly obvious way, most notably the very real pain in her eyes. Keeping quiet isn't an option, though, and she knows that. "There was a fire. I was... young. Maybe five. My mother threw me out a window, then she went back for my baby brother. I never saw either of them again, or my father." There is an urge to say more, pushing against her chest like her heart is an over-inflated balloon, but it's not specifically to do with her family, and she swallows thickly until it goes away. Not that it vanishes entirely. "I can't even remember their faces properly."

Still, it's better than talking about the man who caught her, who stood with her and made her watch the building burn, the heat of it on her face and the cold of the snow underneath her small feet. It's still better than talking about what came next.