If the aircraft commander misjudged the reason for the engine failure theres two co-pilots who can make their own decision. The crew woud not have continued without the agreement of all three pilots. Plus there's a whole load of engineers at the end of the satphone who can analyse the engine too. Flying a 747 is not a one man show.
Who said the aircraft commander missed being able to land at LHR? IIRC the intention was to go to MAN fairly early. You are obviously not familiar with re-clearance operations on long range flights. This is no different to a practice a 747 might use on 4 engines when tight on fuel. Not going to make London from Hong Kong? Plan on Helsinki. Think you'll make LHR when you get to HEL? Then plan on going to Copenhagen. Looking like you'll make LHR with reserve fuel? Then continue. If not then divert.The fact that they elected to go to MAN rather than LHR suggests rather better judgement than you give them credit for.
If you want to transport an extra engine to LAX then you don't just 'lash it on' and go. Have you any idea what fifth pod carriage does to fuel burn and range?
I'm afraid with every post you are just demonstrating the paucity of your knowledge not just of the 747-400 but also of long range operations and of the conduct of this particular flight. I'm afraid you are out of your depth on this one so please let it drop.