Echo and other members of the Ice Nation (Azgeda) distrust the Sky People.
In Polis, King Roan faces an insurrection. His legitimacy is tied to his alliance with the "Skaikru" (Sky People). Watch The 100 S04E02 1
Bellamy and the team originally plan to take the generator back to Arkadia to ensure the long-term survival of their people against the coming radiation. Echo and other members of the Ice Nation