The Human Game: A Shrine for a Fake God

I'm a little worried that when Cancel said "The bridge can carry three people at once, two people carrying the chest, or one person carrying a chest," he meant that only those specific combinations are valid. If so, the person who goes across in step three of Arcanuse's solution should go across holding the chest with the other person on the bridge. Otherwise, there'd be one person carrying a chest on the bridge alongside one who isn't, which isn't a specified combination.