In human decision making behaviors, people rely on random selection processes, such as flipping a coin, to handle a situation that involves so much uncertainty that it subsequently becomes difficult for them to rationally judge a decision. For bilateral multi-issue negotiations, given even bargaining power and two-sided uncertainty, negotiators are often faced with difficult decisions that can not be handled through using a rational strategy or even flipping a coin. A deadlock situation that both negotiators refuse to act upon with incomplete information and at the same time do not want to disclose more information may occur during a negotiation; then, there is a need for mediation. We propose a mediation protocol that is based on the Single Negotiation Text (SNT) device suggested by Roger Fisher. This protocol provides a deal construction game to both protagonists, which not only ensures a rational strategy but also produces better outcomes than flipping a coin.