Okay so i tested your spell.. It's really cool, only thing is you have no need for my first trigger considering they do not exactly get "summoned" and they run around for 20 seconds or so haha.. So remove my trigger, and if you wanted the summons to go up and do 1 critical attack and then die, use my second trigger..
But if you wanted them to last 3 seconds or so, change that in the object editor under your ability dimentionless.. I suggesst they last 5 seconds with .10 second intervals. It worked great for me!