You did well. Your Patronus is strong enough as it tore off at the dementor. The dementor in turn forgot about its prey and it glided off in a great hurry.

Congratulations. You have saved the woman’s life.

The woman, shaking heavily with fear and cold, looks around at you. “Is i-it go-gone?’’

My, my. Look at the state of her. Perhaps you can offer some other assistance.