They may want to do just a pure air-to-air with a large strike formation solely dedicated to an airborne battle with a view of trying to shoot down some PAF aircraft. In that case, the PAF jets would need to fire first if they feel they are getting into the launch zone of IAF jets. Do we think the PAF will take the initiative like that from the decision making cycle we have seen of both the PAF and PA ? They have never struck first, but if they don't do that in a BVR joust, then they will suffer losses.
The historical engagements were for the IAF to perform a 'hostile act' which was a ground strike of some description and then respond to that hostile act, but that was always because the IAF jets had to move into the launch windows of the PAF jets for that hostile act to take place.
A pure air to air would change the calculus and decision making cycle. Hopefully if something does kick off, the PAF have thought of this possibility and have an action plane in place already.
All speculation of course, based on the new of some new blackouts!