This was an official duel, why the fuck would he make the idiotic assumption that they'd execute him? They'd destroy their image more than he already has.
I don't see why he didn't just kill them. They took his allies hostage. And how was he to know how to pass or fail this bullshit test?
He should have killed them to send a message
How did he come to the conclusion that they're both dead? Their bodies were never found.
Also who is he to day that she's nit the type of person to go to the club? Adults have their hobbies too you know.