Although the history of the Sixth Era records that Fiona Drago was the second principal of Saint Byrons Integrated Academy, which suggests that Miss Feliana and Miss Orland are likely to rescue her, it's also possible that another witch inherited her name to commemorate the school site gained through Fiona's sacrifice.
Moreover, Shard promised Fiona that he would take her out. Having gone through so many adventures and walked such a long path with Fiona, a promise given must be fulfilled:
"Hold on tight to me!"
He was ready to confront the descending God of the Night in its unknown form in the last thirty seconds and then leave with Fiona. He didn't need to win, as long as they left the City of Eternal Night, it was victory. He didn't believe that without the Divine Descent Ritual, the power of the God of Night could extend beyond the City of Eternal Night.
