Had to come look on here to see if I could get a hint on what I just died too, guessing it was the sound cannon if it was layer 4, glad I was not wearing headphones... I took a clip of my death and still can't see it even though I was standing still at the time.
Yeah ears went down and had internal bleeding, rolled down a hill and dropped 10m+ onto my head so it did not end so well. Looking at it again there is a very suspicions dead bush nearby so I'm guessing it was in that.