OP, I find the easiest way to stop speed runners is to : show up at item level (hide your Nexus weapons) and don't use AOEs or use very few, pretend to run out of tp...and let the tank die a few times (you can do this as a Dps to) All the while no one will ever know what you are doing. Most times the tanks just Rage Quits. Remember, "There's always a way"