This may have occured to other people - it's always bugged me - and I'd be interested to know what you think.
In 'Clyde Bruckman's Final Repose' (Season 3), when Scully asks Clyde (he is the guy who can see how people will die) how she will die, he tells her that she doesn't. Which is weird, but then in 'Tithonus' (Season 6), Alfred Fellig (the photographer who cannot die) saves Scully's life by telling her to avoid looking at Death.
Alfred Fellig became immortal when he himself avoided Death's eyes years before. So, it reasons that if he took Death from Scully, she would then become immortal. Which mirrors what Clyde Bruckman said to her years before.
I hope this made sense, but I'm interested to know if anyone else picked up on it, and or what your thoughts are.