-— the Israelis have some ballsy operatives who can get high explosives into a secure facility. ——
The only scenario that I can imagine would be the Israelis threatening the family of an employee, forcing the employee to smuggle in explosives. But it’s hard to imagine an employee smugglling in a significant amount of explosives.
My alternative theory is a tunnel. But that’s probably too far out.
How about an employee who had relatives or friends killed during the '09 protests after Ahwannajihad stole their election? Or someone who's father was tortured to death by the Islamists? There's no shortage of people inside Iran who hate the current Iranian government...maybe they just got a bit of help from the Mossad?