I do not know why TWA 800 went down. I know with absolute certainty that the CIA film showing it climb several thousand feet after it blew up was aerodynamic fantasy.
The front of the plane detached and that would cause an immediate pitch up and stall and with the front section gone it would in effect be a flat plate relative to aerodynamic drag. That aircraft pitched up violently , stalled and dropped like a rock. It did not climb, and the turbines would have went to idle and not continued to give thrust. What the CIA showed was a lie. I do not know why they lied.
The aircraft was probably doing about 250 knots when it exploded. If all the kinetic energy was transferred into a climb it could not have climbed a few thousand feet. That did not happen. This is just plain physics. It did not happen that way.
It was climbing at about at about 33 feet per second and doing 376 knots according to the last active radar ping received before the initiating event. It was at ~13,800 feet when the event happened.