It absolutely chilled Billy to the core how quickly Kang's body deteriorated. He took it as a warning sign to clear the distance, taking shelter behind some solid-looking debris and shooting from there.

When the explosion lit the battlefield, Billy swallowed his grief. He had to---he could still hear Kang's voice in his head telling him to keep going, never to let sentimentality get him killed. With that thought, Billy charged, swinging his lance with pure calculated fury. He ensured that anyone Kang hadn't managed to destroy was stopped.