I'll admit I've lost aggro to a few WHMs during the Brute Justice fight. Even after a pre-planned Salted Earth, Unmend and Plunge, he still has the urge to go after the healer, but I have been grabbing it before the tank buster though. I know on my very first go around with him, I expected to get it with just a Salted Earth, Unmend and Scourge, but that didn't seem to be enough somehow and a healer ate one xD