Itachi would snicker at the two girls, finding their reactions to be amusing. He leans in towards Risako and smiles at her.
"Don't worry about it. After all, odds are the person you know and I aren't all that different!"
He sits back and goes between the two girls, talking slowly to allow them to intervene when necessary.
"Ah, yes. Dimensions, as we call them, the infinitely expanding planes of reality. Of course, every dimension has some overlap with its many neighbors. This space contains such overlap, and as such, has different psychics than any other dimension. Time doesn't flow here, so naturally many use it for recuperate and planning. I find that my associates use it to compare research, too."