When Hurley was talking to Jack in Santa Rosa, he said:
…because we are dead. All of us. All of the Oceanic 6, we are all dead. We never got off that island.
A recent Discover Magazine had an article about teleportation. One of the methods of teleportation involves teleporting the information within the particle. Here is the excerpt that relates to Lost.
In these teleportation experiments, physicists start with, say, two atoms, A and C. Suppose we wish to teleport information from atom A to atom C. We begin by having a third atom, B, that starts out entangled with C. Now atom A comes in contact with atom B, so that the information content of atom A is transferred to atom B. Because B and C were originally entangled, A’s information has now been transferred to atom C; someone examining atom C would be unable to tell any difference between it and the original atom A.
The entanglement destroys the information within atom A (so we don’t have two copies after teleportation). This means that anyone being teleported in this way would die in the process. But the information content of his body would instantly appear somewhere else. In other words, he would die in one place but be reborn in another.
If the Orchid station really does have something to do with teleportation, and if the Oceanic 6 left the island through the Orchid, then Hurley could be experiencing a nature scientific side effect of teleportation. According to the article, they did die on the island to be reborn off of the island. Maybe the writers are giving us a clue as to how they left the island.