To the OP, and I know this has probably been posted, forgive but my time is limited so I couldn't go through it all ..
However.. police stated early on that they found the exit door propped open.. I think we'll find, and it's already a pretty popular idea.. that the
shooter himself was in the audience, faked like he got a phone call, got up and walked to the exit.. propped it open, went to his car to put on his
gear and then re-entered via the propped open door.
Why fake a phone call? .. it's less suspicious than just walking out the exit.. if you fake a call then you look like you're just trying to be
courteous .. his car was in fact parked by the exit and from what I've read, he's said he purchased a ticket for the movie so it stands to reason it
was him .. it makes perfect sense.