I’m not surprised you didn’t get infected. You did what was recommended and it worked. I’m happy for you, though.
I’ve been a double mask wearer since day one. It just makes sense. I had a similar encounter with an unmasked (and infected) person in an indoor environment-he was also not respecting the six foot distance recommendation, but I was double masked. It was indeed scary to find out that he became symptomatic that night, which was the catalyst for my own covid test. Waiting for my test results was nerve wracking, but when it came back negative, I counted my lucky stars that I had thought to wear two masks. And I became very assertive with regard to enforcing protocol after that!