to shut it down in order to recover its guidance device. AMEE wounds Burchenal and pursues the others before fleeing, perceiving their actions as a threat. Gallagher informs the others that she has entered military mode and plans to kill them all one by one. She wounded Burchenal rather than killing him because she was trained in the old guerrilla tactic that a wounded man slows the enemy down. Gallagher builds a makeshift radio from parts of the Mars Rover Pathfinder, through which Bowman instructs them to use a Russian probe's sample-return system to launch themselves into orbit; Bowman tells Gallagher that the probe can hold only two people. The trio seeks refuge from an ice storm inside a cave. Pettengill flees with the radio, devastated by the recent news and terrified of being left behind, only to be killed by AMEE. After the storm passes, Gallagher and Burchenal recover Pettingill's radio from his body and discover that it has become infested with insect-like native Martian life (identified by Burchenal as "nematodes"). The insects are highly flammable, as evidenced by the chain reaction that occurred when a simple cutting torch was used on Pettengill's corpse to free his grip. Later, the two come across a field of algae being eaten by insects, and Burchenal figures out what happened: The Martian insects had lain dormant on their nearly dead world, but when Earth's probes spread algae fields across Mars, it provided them with a massive new food source, resulting in a population explosion. The Martian insects are responsible for the algae's demise, but in the process, they provided Mars with breathable oxygen levels because they produce oxygen as a waste product (explaining why they are so flammable). The insects were also responsible for the habitat module's destruction, as they tore in to get to the food supplies inside. Burchenal explains to Gallagher that the biochemistry of alien insects' respiratory metabolism is capable of producing oxygen far more efficiently than human science can. Studying the insects' biochemistry is the key to terraforming Mars, and may even lead to discoveries which will allow Earth's polluted atmosphere to be repaired. However, Burchenal is attacked by swarms of the insects when blood drips from an open wound. Rather than be eaten alive, he passes his sample vial of insects to Gallagher before immolating himself and his attackers. Gallagher arrives at the Russian probe, discovers that