According to several high-level sources in the production, Lin had hit his breaking point over the steadily increasing creative tensions with Diesel, as well as difficulties with the star’s sister/producer, Samantha Vincent, who often acted as Diesel’s emissary. A key source of discord centered around the script and its ending. While a cliffhanger was always part of the “Fast X” plan, several drafts of the screenplay also hinged on a jaw-dropping twist in which Dante is revealed to be the true father of Little Brian. Some members of the film’s team felt that the late-game turn was the perfect, if deeply dark, way for Dom to reckon with the concept he held most dear: family. The proud patriarch of the “Fast” clan would have to put his life on the line for a child who wasn’t biologically his own — who was in fact the offspring of his most feared nemesis. Others, including Diesel, felt differently.