Mason has never been forced to fight so seriously in his life, he was amused by Liam's strength and would wish to test it, but now is not the time to try to test his strength. He enters Liam's mind mid-fight and forces him to stop fighting.
They began a mental battle wanting to break each other.
"Tell me something. Why are you supporting this mission?" Liam asked.
"Is this a fight or an interrogative session?" Mason replied.
He ultimately lost this mental battle and was incapable of fighting. Liam had seen his memories and saw that Mason and the residents of this island had been waiting for Nexus' return to complete his mission of literally ending the world.
That is Nexus' goal, to end the world with no true reason or context.
That's what they were taught. 'What kind of plot is this?' he thought.
He felt Nexus' presence and noticed him in front of him. "Here to stop me, Liam?"
"Even if I have to kill you," Liam replied coldly.
