So long story short I got attacked by a dragon and it landed directly in front of me. I went to use "Unrelenting Force" to stun it, but forgot that I actually had "Whirlwind Sprint" (fully upgraded) equipped. So my character sprinted straight through the dragon, and when I turned around to go back to the fight I saw the dragon keeling over, dead. I did not land a single attack on the dragon.
I tried to repeat this intentionally with a second dragon, but it didn't seem to work (my character seemed to get forced off to the side instead of going straight through the dragon).
So I'm wondering, has anyone else killed a dragon using Whirlwind Sprint? Is this an intentional gameplay element, or a bug, or did some other random thing that has nothing to do with my shout kill the first dragon?