A brand new tale of Onkelos and the mezuzah

There is a famous story about Onkelos the convert, who angered his uncle Hadrian by converting. The Talmud relates a story, which I will take from an article about Onkelos:

Once more, Hadrian sent a company of troops with high officers at the head, with the express orders not to say one word to Onkelos and not to answer any questions, but to arrest him immediately. 

The messengers arrived and started to carry out the emperor's orders without delay. They led him out of his. house. At the door Onkelos stopped, and joyfully kissed the Mezuzah.

The messengers gazed at him in wonder, and could not restrain themselves from asking him:

"What does that thing on the door symbolize, and why are you so happy at being taken to Rome, where your uncle will surely have your head chopped off?" 

"I laugh at foolish people. A king sits in his palace and has guards around him to protect him from danger. But the Jewish King, the L-rd of the world, allows his servants to sit quietly at home and He protects them from outside. That is the Mezuzah on our door!" 

Whereupon, the royal messengers took torches and burned Onkelos' house to the ground. He gazed at the ruins and grinned wildly. They asked him why he was so happy, and he replied, "See! While the entirety of my home and possessions are destroyed, look to see that the Mezuzah has not been burned. Hashem cares, at least, for his ritual religious objects! At least, the Mezuzah protected itself!"

The royal messengers fell entirely under the influence of Onkelos's words and it did not take long before they also became his faithful disciples.

All right, the Talmudic narrative does NOT actually contain the section I highlighted (and indeed inserted) in bold above. I would not have expected the Roman soldiers to be convinced by this argument, if proffered by Onkelos. But perhaps Rav Yehuda Deri has a different girsa in this gemara. After all, as Yeranen Yaakov relates, via Kikar Shabbat:

This comes from an interesting article on Kikar. After a rocket hit Be'er Sheva yesterday, its chief rabbi, Rav Yehuda Deri, talked about the miracle that occurred.  He said, "We had a supernatural miracle here.  2 homes sustained great damages.  Everything around the mezuza was destroyed, except for it.  The mezuza remained whole despite everything that occurred."

Snark off, I suppose. I guess one can take this as some sort of miraculous sign of encouragement, that Hashem is with us despite these trials and tribulations. But seriously, perhaps they should check their mezuzahs, to see if there is anything wrong with them.