Shyvana E + BotRK + Bloodrazor trigger order?

So lately I've been playing with a new build on Shyvana that at first glance looks like the dumbest thing ever but it's been destroying everything and everyone in its path. I want to learn more about how this build is as strong as it is, and one thing I can't seem to figure out is the order that all this % max hp is proccing at? My full combo (E-W-AA-Q-AA-RH-AA) with Lethal Tempo takes under 1.5s at full build and has deleted anyone who tries to fight (the second AA can be removed for quicker disposal). I was hoping that by learning more about how my damage applies I can use this build more effectively and try to improve it as well. Any insights you have are greatly appreciated. The full basic build (for reference):