Ever think the ai didn't want to die??? Think of fighting the ai as fighting the ai in a chest game, they are meant to play defensively because the ai is trying to make the most use out of the units out against you at any given time. Think about when you are in the devils layer, the stealth vandals are like horsemen pieces on the board, meant for a quick in and out strike. When you are focusing your attention on the other targets the stealth vandals and dregs will move in from different angles to close distance. The more distance covered before they are figured out then likely they are going to be efficient and kill a guardian. Stealth vandals use others as cannon fodder as they sneak up on you. In all honesty if you watch the ai fight each other in skywatch instead of fighting them, you might think of them as clever little bastards. Fighting the ai is meant to be annoying because the ai wants to give you a challenge, not hand out free kills left and right.