Rocket Boots and Parachutes are disabled in RBG just like arena. Also you cannot BoP flag carriers to prevent people from griefing games.
If a warrior's health was that high, he obviously was being healed by a resto shaman and had last stand up. When last stand expires you lose that extra health and the resto shaman *could* have been CCed long enough to not refresh his buff. That would mean the warrior would lose around 40% of his health from cooldowns which would have been around 300k. *rough numbers and guesswork*