I'd want to see some tear down pictures to understand how that could happen. Running on oil at WOT doesn't make sense to me It would require a very interesting part failure to convert a gas engine into a diesel engine.
A friend that was a heavy equipment operates told me of a D8 size Cat that lost its' governor. It couldn't be stopped as rpm went through the roof and it wound up running on oil from the pan. The operater jumped off and it ran till it crashed into a basement of a house.
I had my 528 motor diesel once when I cranked it and sprayed fogging oil into it.