I could have stopped in time, though I was initially assuming he was just changing lanes. I slowed down in anticipation of him changing lanes and just continuing to drive - as you normally expect people to do on a road - not cosplay as a "road closed" sign for no apparent reason. When it was clear he was actually dead stopped I was like yeah, nah, hooroo and went around as that lane actually goes around the corner and down the hill a ways (you can see a van in the distance who's still on it).

We were already mostly past him when he decided to accelerate in to the side of us. I'm guessing he had a brain snap and was like HOW DARE THEY. His second complaint was that we were going too slow that's why he went around, which I assume translated in his mind as "losing" the race home if we went past him again.

There's one benefit to having multiple vehicles and that is that the joy of sharing a dashcam video outweighs the inconvenience caused by having to send one of the spare cars off to the panel beaters for a week. I live to give to you guys.