Edit, seems I didn't properly read you statement. An infinite expansion has nothing to do with infinite possible outcomes.
There's no way to be sure that the math is describing 'only' our known universe. It could be describing the multiverse, parallel universes, or even both, or something as yet unknown. However, an infinity of infinities makes some weird sense if the mutiverse folds back upon itself on the smallest scale (like a parabola) remaking the universe(s). Conditional, where size (space) is not relevant throughout the system.
However, the big bang has a few knocks. Possibly as many as four (we will see). You may need to consult M. C. Escher (impossible figures).