Watching "The Battle Over Citizen Kane", I noticed at least two major audio "pops". One was at 3:05 into the first chapter the second was at 3:52 into the final 11th chapter. The second one is accompanied by some diagonal lines across the picture. I was concerned before I watched the documentary because I noticed the disc was scratched from behind very slightly on the outer edge of the disc. Can someone tell me if these discs all have these pops or if my disc is damaged? Also I'm not familiar with what part of the disc is read first, does it start from the outside and work in and work inside out after the layer switch or vice versa. And are scratches on the backside of a disc that penetrate the metal more serious that an exact same size scratch on the front plastic? Any help is greatly aprprectiated.