I think there must have been a secondary effect to get this big a fire from an engine failure - loss of engine controls to cut the fuel (a la A380/Singapore), or shrapnel damage to a wing tank that then fed the fire.
The flames (and soot, once the smoke cleared) seem to be on the inboard side of the engine, not centered on the core.
I guess we'll get closer and sharper pix, and more details, fairly rapidly.
BTW - I heard at least one interviewed SLF comment on the "crazy people" who stopped to collect carry-ons. So some passengers do understand the situation.