If the problem is the bees with Final Sting during the Teratotaur then it's definitely a problem with dps not killing the bees (as long as the tank isn't dying outright, which would mean he's not doing the doom mechanic correctly). Those bees that are summoned are not hard to kill, so unless both of your dps is undergeared or unaware, you should be easily passing this dps check. Heck, if the tank was gear level sync'd he could have switched over to damaging the bees and probably killed at least one of them before they start casting Final Sting.