In the fight in question you don’t see the real group damage until the worms have nommed enough and then boom to everyone. It is imperative that ALL dps stop and kill the worms. It’s true that it should be more priority for rdps to generally manage killing adds and all, but mdps is sooo not excluded.
You should go and try to run a healer in some of the SL dungeons and you’ll get it, trust me you’ll get it. XD