How?
She wonders how this could have happened…
She saved Boq's life, and he sets out to kill her. Though it's understandable, considering his heartless condition.
She rescued the Lion Cub, and he grew up into a Cowardly Lion who goes with Boq to kill her and get courage.
She wonders if the Scarecrow is another creature she saved…also coming to kill her…
Probably, she thinks, waiting for death. And she still wonders how it happened.