According to Osho, on March 21st the personality 'Rajneesh' vanished like a dream upon awakening; nothing happened to Rajneesh—he was never real. What happened was total awakening: the seed of unconsciousness burned, leaving only vast, centerless consciousness. Therefore it was seedless samadhi (nirbija): no return, no dark corner to fall back into.
He woke up from the dream of being Rajneesh, and that dream can never come back.