Visible crew/equipment: When Kobayashi and Edie are meeting, what appears to be a boom mike is visible above Keaton's head when the group is seen through the window.
Visible crew/equipment: When Verbal drops the Zippo lighter in the police office, Chazz Palminteri leans down to pick it up. When he leans down out of frame, there are 2 "C-stands" visible in the background. These shiny, adjustable stands are general-purpose utility holders on a movie set, used to position lights and light control material for a setup (i.e. flags, scrims, diffusion, etc).
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.