This show makes my brain race so much. If there's only one place to cross, how did Baldwin get to our world, in such a way that the security forces on our side weren't aware? They seem to keep a pretty tight rein on people who cross over, so even if she had a visa and came over, Quayle should have been aware that she escaped her escorts whose job was presumably to keep her from learning too much.
And if there was a near extinction-level pandemic on the other side, why does their Berlin have so many more newer buildings in it?
Also, Baldwin/Nadia are in their 20s, right? If so, that means them being on the subway platform at age 10 was at least a decade after the split between the two universes -- so why were there lives still identical to that point? I mean, on Baldwin's side, the pandemic had to have already started. (If the pandemic is what triggered massive research into bio-science, and that research resulted in our AIDS drugs, that research has to have been underway by 1995 at least.)
I'm optimistic that the show will eventually explain enough of the history that this will all make sense, and terrified that it won't.