The area in question is the tan debris field that resulted from something striking the 747 just after the last transponder return at 31:12. That had a passive radar signature clocked over Mach2 and took out seats, passengers, luggage, papers, etc., all found in the "crosswind debris field," including heavy items blown back beyond the flight path. A ground-to-air rocket motor was later recovered by a fishing boat in this field, photographed, but then "lost." The "red zone debris" contained wreckage from the nose: seats, passengers, luggage, papers, carry-on stuff. . . Etc. The green are is where the main body of the 747 fell after a ballistic trajectory from the initiating event. . . calculated by the USS Rude which sailed directly to that spot based on those calculations, and found the sea burning from the splashed in 747 and floating debris.
There is no USS Rude. Never has been.
What you're seeing here is the 9K33 Osa (NATO code name SA-8 Gecko) battlefield portable SAM system. Some variants of the missile used on this system can intercept targets as high as 42,000 feet off the ground. Because the 9K33 Osa system was widely exported to Arab countries, on possibility is that terrorists "jury rigged" a single missile launcher plus guidance radar onto a small New England-style fishing boat; as such, this SAM is far more capable than any MANPAD and because the missile was radar-guided, that may explain why the explosion happened at the center of the plane because the missile homed in to the center of the big radar return from the 747.