"I'm no philosopher," Cullen says dryly, "but who's to say all these different worlds don't simply exist alongside one another? It seems the simplest explanation to me, given... everything."

Frankly, he's not thinking too hard about why she's suddenly here. No doubt it will trouble him, before too long. Right now, however, he's still in a state of shock, to some extent. It hasn't fully sunk in.