We have to carefully distinguish between what goes on 'inside' a black hole, and what goes on just 'outside' a black hole. Nothing may escape from inside a black hole, however, it is perfectly OK for matter just outside the black hole to escape. This is where physicists believe X-rays and Gamma- rays are generated just before the radiation-producing matter falls inside the black hole and stops radiating light to those of us who live outside the black hole.