" That 's why I thought you might be ill . " Sanzo 's frown deepened as he stared at the ground and ran a hand through his hair in distraction . " ... I ' m sorry , " he mumbled , shocking Hakkai and not paying attention at all to what he was saying as he retreated back inside .

Question: Why might have Hakkai been shocked by Sanzo ?
Answer: Hakkai might not have been expecting to hear Sanzo say he was sorry .Hakkai might have been expecting to hear Sanzo say something .Hakkai might have been expecting to hear Sanzo say he was sorry .Hakkai might not have been expecting to hear Sanzo say he was not sorry .