He rolled his eyes because of Roar's unenthusiastic but uninformed reply. The he began preparing for the upcoming fight.
He had two options now. He can either wait here out in the open for the fight or venture down the tunnels into a cramped space to fight the ants on their home ground.
He chose the former option. He picked this choice for safety and because he believed that he wouldn't be able to prepare for the battle quickly enough if he went down the tunnel.
The reason he believed that he wouldn't have enough time to fight in the tunnels was because he could already hear the loud thumping sound of a many-footed giant rushing towards him.
This loud sound of a giant with more than two feet in a hurry was coming from the ground. It indicated that he was running out of time to prepare for the battle.
So rather than go down, he began preparing for the fight. His main preparation was to bring out his new Blade Swarm hybrid shield and the golden bow.