1st rule of gaming - SAVE OFFTEN AND IN DIFFERENT SLOTS.
But even if you're not willing to reload an old save, this quest is a minor side mission, to be honest it unimportant, the rewards are nothing special, the xp isnt great (but nice all the same) and as far as i know it doesnt affect the story.
So as far as I am aware, just ignore it and carry on, a hero can't save everyone and mark it down to experience.
and remember to SAVE SAVE SAVE, not just quick save, make regular custom saves and name them appropriatly, e.g. preEnter_Temple etc
