You may want to read the first two parts of this theory to get the full information.
Remember Faraday's rocket clock experiment?
He seems to be upset when he compares the two clocks. We might assume that is because the times are different. But he must have EXPECTED the times might be different, else why send a rocket with a clock in it. He was most likely upset because the clocks were not of the same type! If YOU were going to do such an experiment, wouldn't you have bought two clocks of the exact same model? So did Faraday!
The clock he now has came from the OTHER Faraday. And in the other alternate polarity reality, THAT Faraday sees the rocket land BEFORE the woman on the ship launches it!
Just as in THIS reality, the dead doctor's body has washed ashore BEFORE he was killed. The doctor WE saw get killed, washes up on the OTHER island, and much later.
In the reality we are most closely following, Naomi gets sent from the ship in the first copter, and she crashes in the ocean far offshore. But a Naomi from the opposite polarity reality seems to land far inland with a phone that isn't quite set up in sync with the phones of our friends, and we see she needs to adjust her phone before they are able to track it. She also has a photograph of Penny and Desmond there would be no way the Naomi in our reality would be able to get a copy of.
In the opposite reality of what we say, Penny kept the photograph instead of Desmond. She keeps it on her nightstand and made a color printout of it on her computer for Naomi.
Stay tuned.