How strange is the creative process?

I remember reading an interview with Haruki Marukami somewhere, and the jist of it was that he didn't really consciously develop the symbolism that shows up in his novels. It just kind of happens. Actually, I'm probably totalling reimagining all that from my own jangled brain, but the point I'm trying to get at here is that for all the planning and coordinating and structuring you do, when you actually sit down at the writing table, things can take completely unexpected turns that seem to come from nowhere.
I'm at this juncture in the work where it's essentially a transition, and I was really trying to get from point Q where we were to point R, which should have been a fairly simple move. And yet suddenly our protagonist has lost the ability to use his legs for no apparent reason, and I couldn't for the life of me tell you why that happened or where that came from or what it might symbolize or any of that shiite. I really don't know. It's just that wierd magic that happens when the blank page is in front of you, and you try to cross the jungle. It's a mysterious thing this creative process. Very strange indeed.