I was in Fort Amol during the Civil War when a Stormcloak with a greatsword and very low health attacked me. I managed to slice once just before a killcam. My character went into third-person, the Stormcloak pulled the sword back whack-a-mole style, and I sliced her through the chest killing her. I had no idea this could happen!
1000+ hours and Skyrim still surprises.