Quote Originally Posted by mebben View Post
Why do you want 10 spears? It takes 5 to shoot him down. Anyway, I find it easier just to head all the way up to the room left of the cannons and park my guys there, killing every spawn as they pop. It will even give you time to regen with your whole team between the adds that will spawn.
So if you don't succeed on the first pass, you don't have to do another spear farming pass.