I refer to Jack and Desmond saying that Locke has to “let go” in order to move on. What I believe this means is that once Locke actually realizes who he actually is in the Flash Sideways and combined with the fact that he has in every reality believed that everything happens for a reason will emerge as himself back on the island. And where will this happen? I believe it will occur in Smokey/Flocke. We have already seen Locke breaking through in Flocke at times. His signature saying “Don’t tell me what I can’t do!” Remember when Flocke was chasing Jacob as a boy through the jungle and Flocke fell down and Jacob told him to remember the rules and Flocke came back with “Don’t tell me what I can’t do!” This to me was Locke’s personality leaking through.
So if Locke personality can spill over into Smokey/Flocke then I think the same thing can happen in reverse. I believe that Smokey’s/Flocke’s exit point is into the Flash Sideways is through none other than Locke himself. The question is who will cross over first?
Now what is the significance of the mirrors to Lost? I know what they mean in Doctor Who but I think they will have significance in Lost. Things in a mirror are the reverse image of what they actually are. With this being said on the island Smokey can take over the form of things that are already dead. I think it is the mirror opposite for the Flash Sideways. He can actually inhabit the body of a prepared living being on the other side which would be Locke.
I also believe that Jack will have to make an important decision in the end. I believe that Locke will cross over first or they both could pass each other in the process. In Doctor Who the Doctor’s memory print was simply wiped from the schizophrenic computer Xoanan. Since island time seems to run faster than reality time I think Locke will have time to convince Jack that it is truly him that inhabits Smokey and Jack will believe that the MIB is truly gone and the quote “I wish you had believed me” will come to pass and the infinity loop will once and for all be broken and the game will finally come to an end.