Seeing that the turtle still wasn't dead, Zim continued to close the distance. He gave a primal yell of frustration inside the cockpit as he brought Black Star got within melee range and releases a flurry of strikes from his thermal scythe. The first slice was horizontal, attempting to remove the gattling guns from the rest of the body. He followed this by rending a large X through what he assumed was the power supply. If the sensors indicated a power surge he would dash out if the way as quickly as possible (H8), re-engaging the invisible aspect of the active cloak with the armored wings down to protect from as much of the blast as possible if he wasn't fast enough. If not, he would continue hacking away until he was certain the turtle was dead. 

Perhaps Zim had gotten used to being in lighter gravity, as he found himself breathing heavily. More heavily than normal, any way. He tried to remember to focus and slow down his breathing.

TLDR: continue to attack turtle with thermal scythe, run away to h8 if its gonna blow!