Between the sudden decompression and the blast wave of the warhead detonation, it was instant for everybody.
I suspect that a blast wave would instantly be dissipated by opposite explosive decompression and fast moving slip stream. Decompression at FL330 would not kill healthy people instantly. Occupants not directly hit by shrapnel or airframe parts during the in-flight break up would become unconscious from lack of oxygen and the freezing air blast. But when descending through lower altitude and warmer air, (FL100) surviving occupants would likely regain consciousness.