The machine lifeforms not only infected the YoRHa soldier units on the ground, they also infected the with a viral attack, activating a self-destruct sequence.
With this, the 13th Orbital Satellite Base was destroyed.
2B and 9S avoided infection from the virus and escaped the Bunker before it was destroyed. Proposal: Find the remaining surviving YoRHa Soldiers and start another descent-to-ground operation on Earth to fulfill the mission.
— www.crunchyroll.com →