What is the effect of a payment made prior to trial to a plaintiff by one of two defendants?

In the case of Dixon v. British Columbia, [1979] B.C.J. No. 304, the court had occasion to consider the effect of a payment made prior to trial, to a plaintiff by one of two defendants. In that case, the plaintiff suffered injuries when he fell on the deck of a ferry. The plaintiff had purchased a bus ticket from the defendant bus line. His journey was to have been by bus and ferry. The defendant bus company contracted with the defendant ferry to transport the bus and passengers from Vancouver Island to the British Columbia mainland. The bus was driven aboard the ferry, where passengers were told to disembark. The defendant bus driver directed the passengers toward a safe route to the deck of the ferry. The plaintiff followed the route but slipped and fell in a pool of oil on the ferry deck and suffered injuries. Each of the defendants argued the other was liable. Before trial the ferry owner paid a financial settlement to the plaintiff in return for an agreement by the plaintiff not to proceed with the action.