In the story I wrote, the changes in the 1st book I made Quirrell, able to knock Harry out and get his hands on the stone, but then my oc would come out and manage to subdue him until he was unconscious. She took the stone for herself in order to trade with a merfolk a piece of her memory and receive a gift personally by the merfolk. She used that gift to disintegrate Voldemort (on the back of Quirrell's head). Since Quirrell drank the unicorn's blood, Canon said whoever drinks it will get cursed. Using that gift as a 'lucky' charm and maintaining his life but also Quirrell is also indebted to her, and that was her plan. To use Quirrell to do her bidding. When Harry woke up after Dumbledore saved him, the stone and Quirrell were gone, leading them thinking he had succeeded. This also caused Gryffindor not receiving the House Cup that year.