Hammond’s and Arnold’s earlier insistence that Muldoon ensure the health and safety of the dinosaurs limited his earlier attempts to stop the rampaging tyrannosaur. At that point, they still prioritized the park’s financial success over the lives of their visitors. Now that the survivors find themselves in a life-and-death struggle, Grant simply poisons the animals. Advanced human technology gives him an edge over the lethally clever raptors, at least when he has access to it.