Comments of chapter undefined of The Challenger's Return: Rebirth of the Rainbow Mage

I don't really get what the point in the thief handing the coin off is. If the fourth group is trying to ambush and kill the other 3 groups, then why would they need to hand the coin off and have someone escape with it? If they fail in their ambush, their group is ****ed anyway. If they succeed, then everyone in the other 3 groups will be dead and there'll be no one to try and take the coin back, so escaping with it seems entirely pointless except to make things difficult for the MC.