Peuce
You've clearly never flown a four engine aircraft before. An engine failure is not necessarily a requirement to divert, in fact a straight failure will usually allow continuation to destination if you are over 2/3's thru the flight.
This failure does not appear to be a time critical event. Although they clearly wouldn't have had the fuel to make destination, it still made sense to leave the aircraft pointed in the direction it was going for 12 minutes while they worked the problem and meant that navigation was one less thing to deal with. Fuel jettison would have taken a considerable period of time to achieve anyway.
Nothing worse than a rushed attempt to return or a quick/wrong decision for a particular course of action when the availability of time has not been established.