Hi,
If anyone did this already you will know that he rapidly does the swift strike...
As a mage you can just pop mirror images, and he will stand still and spam the swift strike, no matter where you move to. (Also after your mirror images die)
EDIT: Some pictures below, showing that he stands in the same position, before and after images. With a timer on it. Sorry for the 1 min pic, screwed up by holding mouse over my elemental.
Don't know how I can prove it otherwise as I can't make a video, this is probably the closest I get.
As said, this is a minor exploit, nothing gamebreaking. But still an exploit.
https://i.imgur.com/rwkJ74P.jpg
https://i.imgur.com/7vzLbBT.jpg
https://i.imgur.com/ScnsA7d.jpg