Honestly I would hazard if they made slightly different decisions they could of all have survived. Except for the amputee. IE: First room had crossbows shooting at them but not a single bolt actually hit the characters, they just got grazed or missed. Entering the chamber to save themselves caused that extra round to happen.
Not going for the empty box and instead letting be offered would of probally kept the extra round from happening.
and of course not voting for yourself because they are all assholes.
And of course the rabbit doesn't believe they ever would so he prepared tortures for the lowest number of people possible.