The movie would have certainly been less entertaining if it wasn't for the universe of the mind which it is way more vast than the real world. Most probably the infinite of the mind can't be real infinite but it sure is much more "infinite" than the actual real world "infinite". The absurdity of extremes is entertaining to delve jump into, as it is often draws some limits to truths.

But why not to have a mind that branches in terms of the probabilities created by the older mind?(the older you is creating the future you, it is not only the nature or physics) There could be a thousand or a million of choices, but they will all need to respect the past and the continuity of certain "laws" of our universe. So, i would say there are definitely never only "two" choices, but just a forever changing hierarchy of choices.