Once the protagonist boards the plane he admits that the letters were a code, but you would have to look at his whole life to understand the code.
Eu entendi de forma diferente. Aqui estão as linhas reais faladas no filme:
Yevgeny Petrov (YP): You know, you were right, there is a code.
KGB General (KG): I knew this. What is it?
YP: You just have to step back far enough, and you will see it.
KG: See what?
YP: My life.
Então, sim, havia um significado maior por trás dos envelopes, e era a própria vida de Yevgeny. Esta linha faz alusão ao seu hobby ao longo da vida, à sua experiência sobrenatural e à premonição de sua própria morte.