During a recon flight, Heater suggested to Mac and Split that they examine one of the fetus fields. Both of them rejected his idea, but he convinced them that by using the dumping grounds as cover, they could avoid the detection of the Machines. They eventually agreed to his plan and headed toward the fetus fields.
As they were flying low to use the dumping grounds as cover, something clipped their ship and ruptured their starboard input tank, making their ship crash on the surface. Mac was able to survive, but both Heater and Split died on impact.