Car fires are the worst. We had a Honda Civic on fire once and it took us an hour to get that one u see control. The Catalytic Converter was white hot, nothing would put it out..
I’m not buying your story.
Yeah, some metals can just keep burning even if you smother them completely, since if they are oxidized, they have their own supply of oxygen to feed the fire.
They did some welding on a metal retaining wall that is on the side of this kind of canal/slip that is outside my office about a month ago. For a few hours, we could see smoke bubbling up from the water, because something just kept burning despite being completely underwater.