An interesting (one hopes) sidelight to the episode....
This is, after all, two stories overlapping...the present story, and the
future story. When, eventually, that future story is shown, it has to be
absolutely consistent with the events in B-squared. So what was required,
really, was to block out two scripts...this one, and the one yet to be
written, so that the events dovetail in the right sequence. (The best analogy
would be the last two "Back to the Future" films.) It was kind of a bear, but
an interesting thought experiment.