Split Second is a 1953 American film noir thriller directed by Dick Powell about escaped convicts and their hostages holed up in a ghost town, unaware of the grave danger they are in. It features Stephen McNally, Alexis Smith, Jan Sterling, and Keith Andes.^[3] It was the only film put into production by the consortium that took over RKO Pictures in late 1952 before previous owner Howard Hughes resumed control of the company.

Armored car robbers Sam Hurley and Bart Moore escape from a Carson City prison, although Moore is shot in the stomach in the breakout. They are picked up by an accomplice, Dummy, waiting for them on a deserted section of road, who drives them to a gas station where Hurley intends to steal a better car. There he murders the attendant for trying to « play hero » – something Hurley absolutely despises – when the man tries to get the jump on him.

After rifling the register they head for a ghost town on the Nevada Proving Ground to hide out. Along the way, they pick up several hostages, first the wealthy Kay Garven and her lover, insurance man Arthur Ashton, then, when Kay’s large luxury sedan runs out of gas she is forced to flag down newspaper reporter Larry Fleming and out-of-work dancer Dorothy « Dottie » Vail in Larry’s well-used vintage woody station wagon. They take up quarters in an abandoned saloon, which clearly has been recently inhabited. Later, its sole resident, hermit prospector Asa Tremaine, appears and is also held. Sam calls Kay’s husband, Neal, a doctor in Los Angeles, and threatens to kill Kay if he does not come and help Bart. Kay doubts he will come, as she is divorcing him and he knows she has taken up with Arthur.

Larry warns the gangsters that the government is going to conduct an atomic bomb test nearby the next morning, but Sam plans to leave before then, though he leaves it unclear what he plans to do with the hostages. When Arthur tries to be a hero, Sam kills him without a qualm. Despite this, Kay uses her feminine wiles to try to persuade Sam to take her with him. To Kay’s surprise, Neal still loves her enough to show up. He successfully operates on Bart, but warns Sam that moving his friend too soon will kill him. Sam waits as long as possible to give Bart time to recuperate.

Unknown to everyone, the test has been moved ahead an hour due to favorable weather conditions. When the five-minute warning sounds earlier than expected, Sam and Bart hurry to Neal’s car, and a desperate Kay barges in with them. Larry overpowers Dummy, but Sam drives away. Asa leads Dottie, Larry, and Neal to a nearby mine. Sam initially drives the wrong way, toward the bomb, and the threesome, and Dummy, are killed by the explosion, which incinerates the ghost town, but the others emerge unharmed.

https://en.wikipedia.org/wiki/Split_Second_%281953_film%29 

Split Second is a fairly taut adventure closely tied to the atomic age but it is rarely explosive …