Hey,
I played yesterday with my friend few 2s arenas. We faced monk and warrior. Warrior died almost instantly and my buddy was at 50k and me at 100% health. Monk somehow managed to get killing blow on my friend and then whoop, Enemy Team wins. I was like what the hell, that can't be. I checked my Combat Log to find out that Monk did a Touch of Death to me, when I was around 100% hp.
I did the screenshot to have a proof
I came back to this game few days ago after cata. Maybe it's a common bug in PVP and I don't know it yet.