Dean eventually finds and burns the doctor's hidden corpse, breaking the spell. The episode ends with Sam answering a phone call from their missing father, John Winchester.
It blurs the lines between the game and reality, ultimately showing the house being burned to the ground (within the game or a new reality) to provide a sense of finality to that arc. [S1E7] Asylum
The doctor's spirit infects Sam with extreme rage, causing him to turn against Dean and even shoot him with rock salt. Dean eventually finds and burns the doctor's hidden