I'm not familiar with the route, but know a little about ETOPS.
Just because an airfield has been nominated as the ETOPS suitable in order to comply with ETOPS, this does not mean the aircraft must divert to that particular aerodrome in the event of a failure.
"Land at nearest suitable airport" (or AB equivalent) still applies- as does the decision making in determining what is and isn't the most suitable at that moment.
If it was clearly safer and not much further to continue, that is absolutely justifiable.