What was the meaning of the scene in which Jack Torrance enters room 237 and watches the beautiful girl turn into a rotting old women?

She rotted into the corpse,.. She was dead

NOPE, your not using your head, or any of the movie analysis and knowledge of the movie...now, the decomposed gangrened old woman first of all is not a rotting corpse sitting in that tub, why is that, dont be a dumbell, the woman comes out first as a phantasm of a young beautiful girl looks sorta like Eve, next she transforms into a decomposed old lady, with Jack getting psyche images of her sitting up over and over again from the bath tub, which obviously cannot really be their and is a complete psyche phantasm, next, the old woman of room 237 is revealed to be Mrs. Massey, who was a visitor that was murdered by Mr. Grady in the Overlook Hotel, its all in the Room 237 Shining Documentary, anyways, the old rotting woman in Room 237 is found out to symbolize in Christianity and Paganism, as the serpent, which is about mysoginists in paganism lore, and is destiny to further transform Jack Torrance into his full cryptid form as a killer for the devil.......welcome.