I cannot understand why this flight didn't return to LAX as that would seem to me to be the safest & most prudent option?
While appreciating your concern the above statement begs the question why is that option prudent and safest?
If a poll was conducted amongst the world's operators of 4 engined aircraft and the question was 'What is your company policy after an engine surge and subsequent shutdown?' I think the answers would be illuminating.
The flight crew of a twin engined aircraft have an easier decision, with the loss of one engine, because there is only one option.
A 747 could lose a further engine en-route and still fly safely.
At some point one has to trust that the people tasked with overseeing flight safety have looked at the various scenarios with dispassionate, but highly informed and educated, knowledge and deemed it safe.
What many are guilty of here is saying that because an engine failed the flight is in grave danger and must land as soon as possible.
The reason this one is generating such shock and horror is because a further problem brought the matter to public attention.
Three very experienced flight crew operated to company SOPs, themselves approved by the CAA, and landed the aircraft safely at Manchester. I am not sure what more they should have been expected to do.
On a technical note, and to add some perspective, a surge will always look dramatic with fuel vapour igniting in the efflux from the engine, it looks very spectacular at night. The flame is momentary and is not in anyway similar to a fire. Also a temperature of 1200°C is 120°C hotter than the 20 sec. allowable overtemp of 1080°C applicable to the RR engines fitted to BA's fleet.