I was on a Brotherhood mission and had to kill a rogue mage in a pub. I waited and waited and all he did was get up, walk around and sit back down. A sneak attack just set everyone else on me, so I reloaded and tried a Frenzy spell. Worked a treat. The mage leaped up and came for me, but Mjoll hit him into left field with a haymaker from her warhammer. He flew across the pub and dropped in a heap at the bar. Score!