T. rex Showdown! is the last scenario of Episode 1. Gerry, Jess and Nima have to escape from the Visitor Center because the Tyrannosaurus has returned.
Jess runs back into the Visitor Center, where Gerry tells her to get out. The Tyrannosaurus rex appears from the side, and hits Jess with its tail, knocking her and the darts in different directions. It rips off the banister near Gerry, and Jess gets back up and runs behind a pillar. The T. rex puts its head next to a pillar to see if it can find Jess. She attempts to grab the darts back, and when she and the Tyrannosaurus is in the right position, Gerry drops a crate on the Tyrannosaurus rex's head, attracting its attention, allowing Jess to grab the darts. She picks them up and runs up the stairs, where the T. rex follows her, only to break the stairs upon climbing them.
Gerry gives Nima the dosage just as she starts to have a fit. She soon calms down, but Gerry tells Jess that they need a way out. They find some scaffolding leading up to some windows. They climb outside onto the roof, with Nima being carried by Gerry. The vibration of the Tyrannosaurus causes Jess to fall, causing her to hold on to the edge of the roof. Gerry tries to grab her, but she slips, just catching hold of the stone above the door. Gerry climbs down to the ground, and tells Jess to jump. Before she can do so, the T.rex barges through the door, knocking Gerry backwards and causing Jess to panic and avoid being eaten.
Gerry gets the tranquilizer gun out of the car, only to find he has no darts. Nima throws him the darts, where he starts to load them into the gun. Jess falls onto the Tyrannosaurus rex's nose, where it throws her to the side and knocks her out. Gerry then shoots three darts into the T. rex before it backs off. Gerry runs to grab Jess, where they run to the car as the Tyrannosaurus charges out the door. They pass through the car and hide behind it. The Tyrannosaurus rex starts to knock the car over with its nose, but only slightly. Gerry contacts Laura, and tells her to make the car move. While Gerry and Jess stay still, the car starts to move, causing the T. rex to follow it.
Jess, Gerry and Nima all meet back inside, where Nima questions them about what happened to her. When Nima asks about her bag, Jess throws it to her. Gerry then tells her about rescue, to which she gets out a gun and points it at Jess and Gerry, telling them that there will be no rescue.
- The Tyrannosaurus rex was probably around the Visitor Center because not much time had past since the Rescue Scene at the end of Jurassic Park.
- When Gerry Harding injects the antidote, Nima's pupils return their clear and undilated form. Gerry utters: "I'll be damned." Gerry Harding also said this in the movie when Ellie showed him the pupils of the sick Triceratops were dilated.
- When Jess holds on to the edge, Gerry tells her that he will catch once he has counted to three. This is an obvious allusion to the first film, where Alan Grant promises to catch Tim.
- The wooden boxes that Gerry throws on the T. rex, from the first floor, can also be seen in the movie.
- When Laura Sorkin starts the safari vehicle, the car drives to the right of the Visitor Center. In the movie, the cars drive to the left for the main tour. Sorkin probably activated a different tour loop. The scenario Bygones shows this tour went to the Marine Facility; which wasn't on the main tour.