Complex sentence: Andrew awakens to discover Lorena is gone, and begins to look for her, finding Louette downstairs, who leads him to the place where she is, a passageway at the bottom of the elevator shaft.
Split into simpler sentences: Andrew awakens to discover Lorena is gone, and begins to look for her. He finds Louette downstairs, who leads him to the place where Lorena had gone: a passageway at the bottom of the elevator shaft.