He doesn't hear her, and there's no one around anyway. He just goes for it, because the garage seems to stretch forever and he's curious as to how fast he can go before he has to turn. He's not bothered about checking out the other cars, he can do that some other time.

Of course, things get a bit hairy when what looked like a car in the distance turns out to actually be a wall. Still, he just laughs and grabs the handbrake, skidding sideways to round the corner into the next aisle.

Nothing she hasn't seen before, really.