A grim scenario, which is perfectly plausible someday. Some excellent actors do a very convincing job of showing us just how ghastly a full-bore torture/interrogation of a nuclear terrorist could be. I thought it was an excellent film.
There is an interesting legal issue our by-the-book lawyer/FBI agent forcefully argues when the rough stuff begins....that torture is unconstitutional. That is far from clear in a scenario like this. I was a prosecutor for many years and everybody's sense that the cops beating a confession out of a prisoner to get them to confess to a crime, even to a murder, would be unconstitutional is accurate.
However, the Constitution actually says nothing about torture. What it forbids is "unreasonable" searches and seizures of evidence. Slapping an arrestee around to get them to talk would be an unreasonable "seizure" of their confession.
With good proof that a terrorist has planted multiple nuclear weapons in American cities---that will kill millions unless the terrorist prisoner reveals the locations, any competent Constitutional Law professor would tell you there would not, necessarily, be anythig "unreasonable" about starting to nip off fingers to learn where the bombs are.