That's a good call, Del, on both counts.
I'm liking that theory a bit more, now... As much as it creeps me out.
And yes, I found Jacob's Ladder disturbing, too.
I think the most disturbing such film I ever saw was one my English teacher showed us in the 8th grade. I forget what it was called, but it was based on a classic short story about a Civil War veteran who is about to be hanged for desertion, but who somehow slips the noose, gets away from the Executioner and his captors, and makes it back home to see his wife and baby. Then, just as he's about to embrace them, he is snapped out of his reverie by the trap door opening and actually being hanged by the noose.
*shiver*
It seems many stories like it have followed - "The Others" comes to mind, although in a different sort of way - you know, that mind playing tricks on you sort of thing.
But your version of DD is actually way more disturbing.
And makes me want to watch it again tonight with a leaning towards that angle...