This study delves into the intricacies in deploying mediation as the primary alternative construction dispute resolution technique before arbitration, with a particular focus on the nuanced interplay among quasi-imposition, Machiavellianism, and the making of idiosyncratic deals (IDs). Mediation is by design a flexible process whereby participating parties can structure their own settlement agreement. Moreover, mediation is now typically quasi-imposed contractually or encouraged by the court. While quasi-imposition encourages attempt of mediation, it may invite the practice of Machiavellianism, a type of manipulative behaviour for personal gain. This study contributes to the construction management literature by explaining the caveats in using quasi-imposition strategy. The conceptualisation of mediated settlement as idiosyncratic deal is also novel in mediation studies.