There are plenty of creatures of appropriate CRs that can either easily be smote in one round of full attacks by the fighter or kill a party member in one round of full attacks, especially if its low hid die class like rogue or sorcerer. DM fudging can come in a lot of ways, damage may just be easier. I can say the Medusa is trying to lock its gaze with yours, oh it failed, and only when I think the fight has gone on long enough so maybe HP attrition would of killed him have the Medusa's gaze lock on.