Vortex nova or needlestorm for Warlock (Cata Nova works but it can be shot by the Walker). Blade barrage, Nighthawk (You need to hit the red glass on the front or the orange bar on the back), or Gathering storm for Hunter. And Tcrash for Titan (Twilight can work but it seems to not be consistent while Burning Maul pyrogale can't one shot due to its horrible damage). Use revitalize for instant full super and you should have I think 4 charges. You can also use cabal drop pod upgrade since it one shots and if you hit them with the charge (Tossing the coin at them) it'll stick to them guaranteed to destroy it.