Thanks for the well wishes! So my friend was behind me and was taking video, but I doubted he was close enough for it to be useful. But he sent me the video, and in fact, he was pretty close but I went out of camera view before I hit the brakes and went down. But what you do see is that I make it through 75% of the turn before I go out of view around the hairpin, and as he rounds the turn I am already on the ground.
So the video is really changing my perspective on what I did wrong. In my mind the truck was out of view until the last moment, but from the video you can clearly see my head turned and looking at the turn exit at an angle where the truck would have been visible. So I was facing the oncoming truck, but was so focused on the road I didn't see it until the last second. Tunnel vision.
Of course the slo-mo from the time I turn my head to the time I go down is probably a second or 1.5 sec, something really quick, and just like on the track, things happen really fast. But if I was looking ahead more and thinking about the possibility of an oncoming car, I could of had more time to respond in a gradual fashion.
The other thing the video of me on the ground, here is a screenshot:
My position relative to the bike makes it clear how I went down. No wonder I have no memory of falling, I basically just got slammed into the ground after grabbing the brake. So I did not go over the bike at all, just a low-side where I ended up in front of the bike. But it appears I could have just not braked at all and there would have been room for me and the truck...
But the lesson for me is more about looking farther ahead and anticipating things before they happen versus not grabbing my brake.