Factual error: A person with 60% burns on his body would not be wearing pyjamas, as the Hungarian guy does. (00:19:45)
Factual error: When the burnt Hungarian guy is interrogated the first time a doctor insists that everyone wears masks (even though Jack Baer is very lax about it). When he is surrounded by doctors the second time none of them bothers about masks. (00:38:10 - 01:01:40)
Factual error: When the Suspects planned to kill Kobayashi, they waited for him in the office building. McManus got into the elevator and waited for the three men, hidden in the roof. After Kobayashi and the two men got into the elevator, and the lights went out, McManus fired twice. The blood on the wall behind Kobayashi would be correct if the two shots came from in front of the men. But McManus fired from the roof of the elevator, meaning the blood spray should be much lower on the wall and angled sharply downward. (01:05:50)
Answer: He never did. How they got on the boat and took out the Argentinians could have actually happened in a million different ways. For all we know, verbal went on the boat with them, and then killed them, which is more likely as it is an extra gun. The point of the film is to show how much of a mystery Keyser Soze is, that even after all of that, no one knows who he is. For example, he tells the story as if Soze is Hungarian and killed his wife and kids, but we know this isn't true, because Kint is Soze and he's American. The point is, he's telling so many lies and making up all these stories, so it's got to a point that they don't even know his real nationality. The only reason we though he was Hungarian throughout the film is because Kint told us, but we know his story was a hoax.