THE END, LAST WEEK, WAS OFF-CAMERA. AFTER THE bloody steps, the heart-rending funerals, the surreal chase through the twilight of Los Angeles, O. J. Simpson surrendered himself into the darkness his life has become. He was in the back seat of his best friend’s Bronco, communing quietly with his cellular phone, his blue steel revolver and a picture of his children. As the police stood back, waiting, the shadows lengthened. O. J., the great halfback who had made a fabulous career out of running for daylight, could no more hold back the night than reverse the tragedy of his week. Above, helicopters hovered, each carrying enough candlepower to light a village. And then O. J. emerged, turned himself over to the police, used his bathroom, accepted a glass of juice and, like sons everywhere caught in trouble, asked for time to call his mother.