The segment about the Trinity test site in 1945 opens with a shot of a large item on a big trailer with many wheels, pulled by caterpillar tractors. The thing on the trailer is not an atomic device. It was a large steel vessel of 214 short tons, called "Jumbo", that had been specially built at great cost for the first atomic test ("Trinity"). There had been concerns that the device might fail to produce a nuclear explosion. This would have scattered almost all the plutonium across the desert. The plutonium had been manufactured at great expense in some of the world's largest factories which had been built specifically for that purpose. The initial production had been very slow and expensive. So the decision was made to order "Jumbo" and explode the device inside it, in order to save as much plutonium as possible in case of a fizzle.
By the time Jumbo arrived though, plutonium was being produced in quantity and Oppenheimer was confident there would be enough for a second test. It was decided not to use Jumbo but instead, hoist it up a steel tower 800 yards from the world's first atomic explosion, which it survived intact. Jumbo's remains are still at the Trinity site. The visible fractures were incurred in a much later test when a conventional bomb with chemical explosive was set off inside it.
Skip Rutherford narrates how at the time of the Titan incident, he was convinced Little Rock, Arkansas would be gone in an instant in case the nuclear warhead went off. That is not quite correct though. At a distance, of 46 miles, Little Rock was well outside the primary blast zone (six miles) and burn radius (17 miles). The city was at risk from fallout, but the radiation would only reach fatal levels if the wind had blown the fallout there in a straight line, and it would have taken at least several hours to cover the distance.
A woman who lived at the nearest farm next to the missile site at the time remembers how her family received a warning from some acquaintance and evacuated to nearby Choctaw for the night. While that took her family out of the immediate blast zone of a potential nine megaton nuclear explosion, at under ten miles distance, they would still have been very much at risk from the thermal radiation (3rd degree burns if caught in the open), radioactive fallout and moderate overpressure effects.