"You really looked into it though...you asked him to bite you," Mokuba pressed. "Is that really all a lie?"

He has to be sure. He needs to judge whether Yuugi's going to be a problem to them or not. He won't risk his brother...and although they were better people than they'd started, Seto and Mokuba weren't untainted by their circumstances. They'd take any course necessary to protect each other. Any.

On the other hand, he does feel a little bad that he'd caught Yuugi by surprise like that, and made him choke on the water.

"My brother couldn't control himself either, you know...and it's way more dangerous if he can't."