if Pakistan does go to defend Saudi, then the messaging on this to the people must be clear, precise and correct and defined what "defending" means. Offensive operations "into" Iran should be off the table, Pakistan should not defend USA bases or USA military personnel either. Any attempt to lie, will cause resentment and given the size of the Shia population in Pakistan, as we saw with the Embassy incident, will create a lot of problems.
I don't think we are there yet, but it is difficult to know what is "truly" going on in MBS's mind, and what he has promised to the USA and how deeply he is, or isn't involved with the USA attack planning on Iran.