While in Pakistan, in the midst of the Indo-Pak War of 1971, Qadir was serving as a senior research associate at the University of Islamabad. After the Multan meeting, held on 20 January 1972, Qadir's colleagues and peers had quietly disappeared from campus. Qadir's close friend Riazuddin invited by him to Nilore to continue and carry out his advanced research at the Pakistan Atomic Energy Commission (PAEC). As an eminent and noted mathematician, Qadir was given the task to calculate critical mass and the physics cross-section calculations. Qadir, at first, adopted the Monte Carlo method for evaluating complicated mathematical integrals that arise in the theory of nuclear chain reactions. The mathematical calculations were brought up to Riazuddin, but Riazuddin already adopted the method earlier. Despite Riazuddin's and his calculations, Qadir then approached a better method to develop the fission device.