It’s surreal. Rose just watched her planet die, far in the future; now here she is, standing on a very much living earth, in the middle of London, among people just going about their daily lives. They have no idea.
They don’t know that aliens exist, that there are thousands of worlds out there, inhabited by people so strange even Rose finds it hard to believe, and she’s seen some of them.
The man standing beside her is an alien too, although he doesn’t look it. And apparently aliens like chips just much as any human. Who’d have thought it?