a perfectly safe decision was made - by the captain.
Indeed it was and it would have been after consultation with Ops/Engineering in Singapore, the Duty Ops Manager and the Duty Engineering Manager would have been contacted, (at 22.00 approx. local) and asked for their opinion which would have been passed to the captain. On today's modern aircraft just bring up a page on ACARS, identify the phone number you want, select the key and within seconds you will be talking, via satellite link, to base operations, clear as a bell.
A four engined long haul transport on three engines is still very flexible provided there has been no fire. The final decision will always rest with the captain but the advice of people who have the 'big picture' is the way to go, if it is possible and above all safe.