SEPTEMBER 21, 2552
343 Guilty Spark convinces the Master Chief that in order to stop the Flood, he must activate Halo, an act only accomplished by acquiring the Index from the center of the Library. The Master Chief procures the Index and is transported back to the control room with Guilty Spark. Before he activates the Halo however, Cortana halts the process and divulges the true purpose of the ring: to destroy all sentient life, thereby starving the Flood. After escaping Guilty Spark and destroying critical pulse generators which would hinder the Halo’s activation, the Chief and Cortana head to a lone Covenant battlecruiser to acquire the captain’s neural interface from the parasitic remnants of Keyes’ Flood-infected body in order to detonate the UNSC Pillar of Autumn’s fusion reactors.
SEPTEMBER 22, 2552
After commandeering a Covenant Banshee to return to the Autumn, the Master Chief and Cortana discover that 343 Guilty Spark has followed them there. The monitor freezes the self-destruction sequence, forcing the Spartan to physically crack the engines in order to destabilize the fusion reactor. Once successful, the Chief and Cortana manage to get to a UNSC Longsword fighter and escape the violent destruction of the ring. In the aftermath of the explosion, they scan the debris field and eventually find a small band of UNSC survivors (Sergeant Major Johnson, Lieutenant Elias Haverson, Corporal Locklear, Warrant Officer Sheila Polaski and even the cryotube-encased body of Spartan Linda-058) aboard a Pelican. Through a series of risky maneuvers, the Master Chief manages to get all of the survivors aboard the Longsword and eventually take control of the Covenant carrier Ascendant Justice, using its impressive slipspace capabilities to quickly return to Reach.