PMLN is in a bad situation. They must win this seat by a massive lead (50,000+) to justify the narrative that supreme court is wrong and nawaz sharif is innocent.
A defeat will end Sharif's politics and party would go to shobaaz or nisaar.
However, a narrow victory would spell big trouble because then Mariam qatri will take credit for it and ask for party leadership. This will never be acceptable to nisaar and showbaaz and thus lead to party breaking into factions Nawaz group, Nisaar group, Shobaaz group etc. just like q league, zia league etc.
An example would be na 246 by election where altaf ***** was in danger but won the by election by 70,000+ lead and thus remained leader of MQM. Kulsoom nawaz needs that kind of victory to maintain their family's hold on the party because Nawaz sharif is disqualified for life.