Failed/rolled back what's the difference? Splitting hairs. As Gordon said it's little more than an APU. Your basically in a 200 ton single engine aircraft in the middle of the Pacific. As for the incident in question I was not on the flight deck so will not comment on the decision making process.
Manufacturers and airlines do not like inflight shutdowns because it may affect ETOPs/ETOPs approvals and makes the media. I'd like to know what caused the roll back and how to rectify it. Shame you can't have direct law on the engines like flight controls.