Hint: DR

Jerec Asyr said:

Solution to the nested cipher ('NIF WE TAFOSP HA VQOD')

Spoiler

I took a wild guess and assumed it's Vigenere like the framing cipher, meaning that line was enciphered twice. The original key 'dr' didn't work - but I guessed the second layer would have a length of two as well. The first response that popped up with a two-letter key was BUT IS FORCED TO HEAR, with a key of MO.

YOU ARE BEING WATCHED
THE ONE THAT CANNOT SEE
BUT IS FORCED TO HEAR
THE ONE YOU SHOULDN'T HAVE IGNORED

Excellent puzzle, @[238765921] - much fun. I spent FAR too long playing with mono-alphabetic substitution on notepaper before I started playing with other options.

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