Think of it like there's a kind of energy inside your cells which when they sense the body is dying, this energy is released throughout the body--healing the injuries while forming a new one to do it. And since you're here apparently, you'll see a few of my past selves running about, and at least a future one that I know about.

[This is actually the first time he can recall having to explain regeneration to anyone in a long time. He's hoping the part about his other selves won't be too much for her.]