A former leader of the Iran-backed terrorist group admitted that “There is no doubt that we have been subjected to a major security and military blow that is unprecedented in the history of the resistance and unprecedented in the history of Lebanon.” But he went on to vow the usual over-the-top revenge anyway.

https://www.timesofisrael.com/nasrallah-admits-heavy-blow-of-device-blasts-which-could-be-seen-as-war-declaration/

But I think their actual thinking was more accurately described by an Israeli news columnist who wrote:

"Their mindset will never be the same. They will no longer view a refrigerator, microwave, or light bulb in the same way. Until their last day, they will never feel safe, no matter where they are. They will live in constant fear of what might explode next."

To which I can add only one word: “Good.”