"Because i said please. Also if i wanted i could break down the door but i don't think that would serve you and me the best. I think we can help each other if we trust each other. Do you hear that? Its my sword being sheathed as a sign of good faith
The door opens, and you see a man dressed in mail, holding a mace. A small room is behind him. He sees the size of the party, and looks wary.
"Friends", he says, "I am in in here to atone for my misdeeds against others. I am allowed out once I gain 1000 gold for my freedom. Would you accept me as a 10% partner? Alistair took all the money I had saved. I would rather earn money from evil creatures than honest adventurers."