You're welcome, Bus, however I won't join you in second-guessing the 747 decision.
I've flown 4-engine aircraft over the Atlantic, too, but under very different rules. On the Nimrod, we used to shut down 2 engines for fuel economy (they still do), then light 'em up again for the return home. That wouldn't translate to Commercial Air Transport but it does illustrate the low risk nature of the situation.
Some statisticians might argue that having had the one-in-whatever-it-is chance of failure actually happen, the chances of another one going are impossibly remote.
Yes, I know about the 747 4-engine flameout, but still...