*lol* - the incident was freaking funny (and I was on the losing team myself).
Doc was invulnerable indeed and kept running around like crazy among the defenders, all going nuts and trying to kill her - took about 40 full hits and had an arrow in the head and was covered in blood - same effect as god mode in single player.
actually she did not exploit the situation, could have killed all of us, but mainly kept running around.
Frankly - if that glitch happened to me, I would have enjoyed it as well, and it certainly drove people nuts...
so relax, I killed her twice since, the effect is clearly nothing permanent. Still can't stop laughing though, was really too freaky...