I find the crew's decision to proceed to the nearest airport to be the exemplary call. They were about in the middle of the flight, and might have elected to fly to destination, but chose to go direct to the nearest airport. Good on them.
Well to be honest I'm not so sure that it really mattered...
Either they had a real non containable fire and the only option was to ditch ASAP
...or they had some relatively minor problem in which case flying to destination or to the nearest airport did not make any material difference.
Quite frankly if your are faced with an actual fire emergency the difference between flying 180 or 240 minutes is irrelevant...