system
Given the following post, respond as if you're commenting on Reddit:
human
I believe that as long as the people going into it are consenting adults, who have done legal paperwork with a third party present, they should be allowed to participate in a situation where they can be killed by another. CMV.

As a lifelong fan of the mystery genre, my all time favorite  novel is And Then There Were None, by Agatha Christie. In the book, ten people, who are all responsible for the deaths of others in the past, but were not held accountable or escaped the grasp of law, are brought to an island mansion, where they are trapped by a storm. At the first dinner, a record plays, accusing each of them of their crimes. Almost all deny, and, by the first night, one is dead. As time goes on, more and more are killed off, in accordance to a nursery rhyme hung in all of their rooms, called "Ten Little Soldier Boys".

Now this sounds exciting and intriguing. Why is it that a situation like this cannot be set up, even if people agree to it. Make it a game show or something. Sure, it would be pretty dark, but if everyone is consenting, why the hell not?

This also applies to something like a duel, where two adults do the "five steps turn and fire".

Try to change my view so I can understand why this is illegal.
gpt
Life is a human right by international law and you can't rid yourself of your rights as they are defined as inherent ("unalienable") to you. Same reason you can't legally sell yourself. 

If you make a right optional, people will inevitably give it up in exchange for money. You tell a starving mother you kill her and her kids will have their lives solved (they will go to college, they will live in a first world country, etc) and she will sign a piece of paper saying she agrees to the deal. You can't possibly have rights at all if they're optional. Now, it's a matter of choosing which alternative you want in your society.