Andrew's father, Jim, looks through the door with horror at the end of the film because he realizes he has lost his son to the monster on the stage. Throughout the movie, Jim represents decency, mediocrity, and unconditional love, which are the very things Fletcher despises. Jim wants Andrew to have a balanced, safe life, offering him popcorn at the movies and defending him during the tense family dinner. When Jim watches Andrew's final, manic drum solo from the wings, he does not see a son achieving his dreams. He sees a young man who has crossed a psychological point of no return. Jim recognizes that Andrew has fully integrated into Fletcher's cult of genius, willingly destroying his physical and mental health for a moment of fleeting perfection. The look of dread on Jim's face is the realization that his gentle, protective fatherhood has been utterly defeated by Fletcher's abusive mentorship. Andrew is no longer his boy; he is a creation of Terence Fletcher.■