: Peter saw only the observers interpretation of the big bang. I doubt that even the observers could observe the birth of the universe. The observers might exist outside time, but since there was nothing before the big bang, you cannot watch the birth of the universe from outside the universe. Because that requires time, gravity, natural laws and dimensions and those were all present in that glass room.
But than again, this is a tv show. And in movies and tv shows anything is possible as long as it is entertaining.