Complex sentence: During his student years, Buñuel became an accomplished hypnotist and he claimed that once, while he was calming a hysterical prostitute through hypnotic suggestion, he inadvertently put one of the several bystanders into a trance as well.
Split into simpler sentences: During his student years, Buñuel became an accomplished hypnotist. He claimed that once, while calming a hysterical prostitute through hypnotic suggestion, he inadvertently put one of the several bystanders into a trance as well.