I had the same Prob. My soloution: U need to kill 2 Giants on each side. Since the aiming is buggy kill the 2 on the left first then aim for the right spawn. Wait till they respawn. If u want to aim, dont hold down the button. it will lock the skill and “kick” you off the tank. only tap the button shortly. this way it wont lock and even if u get kicked off it wont turn completely. Hope it helps.