The Dark Knight Rises
Dr. Pavel met up with a CIA operative to be escorted via airplane back to his home. When he met up with the CIA operative, a militia man (Barsad) revealed three prisoners with him who had tried to capture Pavel. The three were brought on the plane with Pavel and were faux executed one by one until the last one, Bane, talked. Bane revealed he was intentionally captured and that his plan was to crash the plane with no survivors on it. Bane's men attacked the plane and Bane did a blood transfusion on Pavel and put his blood into a dead man and left the corpse on the plane. Pavel was grabbed by Bane and pulled out from the plane before it crashed. Pavel was presumed dead in the crash. Bane, while escaping with Pavel, also promised that the fear will "come later."
Six months later, Pavel resurfaced when Bane took the board of Wayne Enterprises hostage. Pavel watched as Bane forced Lucius Fox, Miranda Tate, and Douglas Fredericks to accompany him and Pavel down to the site of the nuclear fusion reactor which could supply Gotham with a great amount of energy but could also be turned into a nuclear bomb. While Fredericks was held at gunpoint by Barsad, Fox unlocked the reactor via his fingerprints and Pavel was forced to create the bomb.
Once he was finished, Bane had the core removed from the reactor, despite protest from Dr. Pavel that it would become unstable in five months time and go off. Since this was exactly what Bane had planned, Bane didn't listen to Pavel and he caused a series of explosions around Gotham which trapped the police forces underground, destroyed Gotham's football stadium, killed Mayor Anthony Garcia and other politicians and officials and cut Gotham off from the rest of the United States.
While the crowd at the stadium was still reacting to the destruction, Bane came out onto the football field with Pavel and the reactor and Pavel was forced to explain the device. After he told everyone that it was a nuclear bomb and only he could defuse it, Bane then snapped Pavel's neck killing him to ensure the bomb couldn't be deactivated.