"If you end your turn on this tile gain X stat." Power farming?
The FAQ/Errata, found here, clarifies that these rooms can each only be used once per player per game. 


  Chapel, Gymnasium, Larder, Library -- Can you stay in one of these rooms turn after turn to increase an attribute?
  
  
    No. Each character can receive the benefit from each room just once per game (one boost for each trait for each player, if all four rooms are in play). Most players find this easy to remember, but if someone gets argumentative, keep a simple, written record.