The Spear of Judgment is the ultimate weapon created by the Constructs, targeting "all humans."
It's quite simple to avoid its attack, just don't be human.
As long as you upload your complete consciousness into the Main Brain, you are no longer human but a Construct, naturally not recognized by the Spear of Judgment.
After the destruction of humanity today, the people of Sky City can survive as consciousness within the Main Brain and become the last spark of civilization, ready to restart a new epoch at any time.
An epoch where they remain the rulers.
Yan Wenwu struggled to move his muddied eyeballs towards Su Mo, with life-support devices continuing to make sounds beneath him.
"Now, I officially invite you on behalf of Sky City, to join us."
"You can bring a few comrades you approve of, and integrate with us into the Main Brain."
