Best case: Righteous Fury on thousands of zombies at once. Flaming zombie corpses everywhere. And until they learn to fly, they can't catch her. Destroys zombie outbreak before it can spread.
Worst case: They can't infect her because she's virtually immune to disease, can't kill her due to her Intervention ability and indestructible armor, and she's nigh immortal. Kills every zombie herself. Realizes everyone else is dead. Goes insane over thousands of years of isolation.
Best case: Uses lost secrets of black magic to take command of the zombie army. Rules the world as Overlord.
Worst case: Lost secrets of black magic fail to take command of the zombie army. Trips over her enormous skirt. Gets eaten by zombies.
Best case: Cures zombie outbreak before it goes anywhere. Hailed as hero and is finally recognized as the genius he is, freeing him from all his pent-up rage and frustration. Laughs at Zombie Pididly before laser-disintegrating him.
Worst case: Sees zombies as next logical step in the Glorious Evolution. Leads army of robo-zombies against humanity.