( The mention of self-defense pings but barely registers. It is his question of names is what catches her interest, has her answering him. )

I suppose the reason why people choose to take up a new name or give themselves a nickname is to make it easier. ( Believe her: If she could have called herself 'Jane Doe' and gotten away with it, she would have. It was easier after all. ) Be it for themselves or for others. I think it all comes down to convenience for many.