Jiang Han wasn't foolish. Having just arrived at the Flying Immortal Hall, he was completely in the dark and didn't want to reveal his strength so soon.
Baili Ju was in the Samsara Realm and a battle maniac, undoubtedly very powerful. Even if he suppressed his realm to match Baili Ju's, he would likely still end up being beaten. He had no masochistic tendencies, so why would he agree to a duel?
"How boring!"
Seeing Jiang Han back down, Baili Ju pursed his lips and said, "Let's go, I'll take you to Flying Immortal Island."