You should have shot him. He WOULD have burned you alive if he thought he could of get away with it. Start carrying a gun.
Your advice from afar sounds over the top from my perspective because this incident was an aberration. Not a usual event. It was threatening but carrying a gun and killing him would be a might "overkill" on my walk in the morning. I seldom see anyone on my walk and except at the truck stop and McDonalds where I turn around, there are no people at all. I live in the country.
There were lots of witnesses and people within close range who saw this incident play out. They would have stopped it if I hadn't deescalated it myself or at least helped me if he did try to do something. Lucky for me, his boss saw him do all this from the drive-in window.
Turns out, he had water in the container, not gas, and he had been drinking. And he got fired from his job and is in jail again. Problem solved without putting a bullet in him.
Bringing out the heavy artillery and injuring or killing the man wasn't necessary. One isolated incident over a decade of walking this route doesn't justify me carrying a gun. Maybe in the big city but out here in rural farm country, I don't need it.