The PM, if he chooses to, could resign any time for any reason. However, the handlers of PTI are hoping that if they could make the PM to resign even temporarily then, perhaps, some kind of 'immunity' given to a sitting PM be gone; and/or perhaps there is some 'dominoes effect' leading to the toppling of the entire setup.
The thuggish marchers have no intention to ascertain the authenticity of the vote! By jumping from the original demand of the recount in 4 constituencies to the ultimate demand of the PM' resignation they have given away their ploy: The toppling of the govt itself. Pray, tell us: Why would the recount be credible a year ago when NS would still be the PM and not now, especially that now there are, reportedly, the COAS as the guarantor? Bull $hit!!