I'm an apple farmer, not a pilot, so take my comments as being what they are ...an interested but clueless spectator.
I live in Japan and had just walked into the house for lunch when I saw the live feed for this come up on one of the news channels. There appeared to be fuel burning on the ground. The fire-crews were already foaming it. One of the live close-up shots appeared to show damage to the underside of the wing (not just the engine cowling) and it looks very much like the port engine had suffered an "uncontained failure".
Passengers reported a single, loud bang from the engine.
A video, which appears to have been taken from the observation deck, shows the plane already stopped with flames coming from the engine and flames on the tarmac. A couple of seconds later a very large plume of white vapour sprays out of the engine (which I assume was the extinguisher being triggered) and the flames from the engine subside, but there are still flames on the ground.
The fire crews were on the scene very quickly and foamed it for a good long while (they weren't taking any chances). Even though the extinguisher seemed to have been quite effective, they concentrated their efforts on the rear of the port engine and surrounding area (including the tarmac).
To an apple farmer, it looked like the captain made a good call on the slides. :-)