You know you're screwed when you start asking too many "why" questions and you don't have answers. You know where you want the story to go, you know where it must end up, but when the whys and hows of getting there were cheated on the first draft, they're going to remain cheated on the second if you only work with the existing words. Simply trying to backthink it all and insert more logical whys is plot jury-rigging of the highest order, and it DOES NOT WORK.
And that's where I'm stuck at.
What I need to do is back off a bit. The answers are there, right in front of me, but due to artificial time constraints, I'm attempting to patch and jury-rig it, rather than gutting the ship properly and rebuilding it, which is what it actually needs.