Then you need to get out more, because it happens very regularly in the lower levels of the game. I had one melee tank go Zerg on me and start sucking up Clerical resources because my Heavy Repeater fighter was out killing him 2-1(only noticed after wondering why we was Zerging) in WW. I know that changes in the higher levels of the game, but in the low levels a solid Repeater Build can drop a lot of mobs quickly with very little risk to the character.