If the Israelis (read USA/UK/France) launch a nuclear attack against either Turkiye or Egypt from Israel, you can rest assured that about 40 or so Pakistani nukes will explode in the atmosphere, about 200 meters above ground, and inside many of the top secret bunkers in the occupied Palestine. Both the Egyptians and the Turks know this, hence their relaxed attitude about it. They both seem to have a certainty about such kind of issues.
Such an attack will only come once all of the occupying leadership is back to safety in their bunkers during a potential war.
Long before that happens, the Europeans will run away back to Europe and abandon Palestine because they will have no more fuel coming their way.
There are many complex scenarios that can occur.
But if anyone thing that Pakistan will not retaliate if the KSA comes under attack or if specifically the Hijaz is threatened, they are living in a delusional world. Pakistan, despite being ruled by a criminal mafia, will set the enemy's house on radioactive/chemical/biological fire. And this is not an emotional outburst, it is something Pakistan knows it will have to do and will do if the need arises.