Consider your world - your universe - everything you know - one layer of many. Some different, some the same. All separate, they don't touch - until now. Something - don't know what - takes us out of time and space, puts us here.
May not be originals. May be copies indistinguishable from originals. Need more data to conclude - could explain disappearance/reappearance of Peeta Mellark. One copy removed, another brought in. Hypothesis only.