Reflex alone made it so Donna didn't even think about shaking the girl's hand. It seemed to just happen, and only after the fact did she process the question. It had caught her off guard, seeing how she'd expected the girl to keep going. "Donna Noble," she replied. "What were you doin' speeding down the sidewalk on that thing? You've got to be more careful! People don't expect to be run over when they walk out of stores, y'know."