My guess is the pilot took one of the slipways off the runway, hasn't bled off all his speed, and is simply freewheeling i.e. making use of the speed he has so as not to use more power while taxiing. I'm sure he disengaged the reversers very shortly after this shot was taken, unless he was rolling really fast! I've seen it done before on 732s, as well as taxiing almost as far as the gate with spoilers still extended and flaps fully down. No harm done, although it is standard procedure to "clean up" once below flying speed. Once off the runway, the wheel brakes are the most effective form of braking, although reversers could be used in emergency (if taxiing in a 3rd world airport with thick fog and all of the sudden you realise your taxiway gives way to the sea or something!).
How do you say "12 months" in Estonian?