PoE Crest of Desire, Herald of Purity builds

Theory tag because I have a PoB and no character to actually show it with. But I've tested the mechanics, and know they work. The question is whether or not my PoB is accurate. Where does the come from? The idea is that buff up , you spawn all your worms, throw the beartrap on your target, then use call of steel 4 seconds later. To do some math: PoB reports that the total stored damage of our Impale is 1 million. The Impaler inflicts 4 additional impales, so each beartrap is 5 million damage in an AOE. With 5 worm flasks and a bit of reduced flask charge