Hey ya'll, been a while, but for some reason I wasn't able to log in. No worries.
I just wanna apologise if this has already been cleared up, or if someone has already posted this idea.
Concerning Mr. Desmond Hume.
Whilst I buy that electromagnetism could send his conciousness back and forth through time, I don't understand how it could send him to a place that exists after death, even though it did. But, despite this, I understand it happened, but didn't entirely understand why he didn't seem to freakout when he first got there.
Then I had an idea.
I'm currently onto the second volume of Stephen King's The Dark Tower series, The Drawing of the Three. In this, Roland of Gilead comes across three doors (I presume, I'm onto number 2) on a beach. When each is opened, he can see into another world through the eyes of someone within that world. In this novel, Mr. Deschain can come forward into that person's body, or go through in his own, if he so wishes. However, I believe that, when Widmore's crazy experiment took place on Desmond, a similar thing happened to him that happened to Roland when he looks through these doors: he saw this world, this afterlife, or this waiting room if you like, through the eyes of his counterpart there. But he was unable to 'come forward' like Roland can (and does). Maybe, he does attempt to at one point, and this results in the collapse of his dead self in the Waiting Room and the return of his alive self in this world (when he meets Penny).
Just an idea.