What? Steven realizes what a fix he's in, then realizes- he's got enough minerals and gas to turn into an Ultralisk!
So he does so, falling at inhuman speeds onto the nonexistent Tazz. This hurts. A lot. He died. Then, Steven uses the small amount of leftover Minerals to create drones, which make a hive, which starts spewing a LOT of Zerglings. Good luck with the Zerg Rush, boys...