So they basically overdub the Polish track over the original Russian? You're right--that's hilariously old-school.
It was done in the traditional style of Polish movie/TV translations, where you have one voice reading the translation over the original audio track.
For example, the late legendary Tomasz Knapik, who has been the voice of countless voiceovers of 80's movies, has also done a voiceover for Kung Fury, including a reminder to rewind the tape before returning it to the rental store, as was common practice back when you rented VHS tapes.
Or the only true localization of Trailer Park Boys with Rafał Walentowicz. It's unique as Rafał was a fan of TPB himself and made up his own slang and joke localizations on the spot that became a part of common language.
It's not that it's old-school, it's just how we do it here. Having Mirosław Utta dub the Russian audio was one of the greatest localization ideas ever. It doesn't just translate the game to help you understand what's going on, it taps into this specific part of your brain, a kind of collective consciousness of people who were born and raised here, that enhances the entire experience in a way nothing else could and no one else could experience it the same way.
Now I'm curious; what's the initial tone and context of that line supposed to be? In English, a phrase like "go your own way" could mean a friendly "keep doing your own thing, you", a cautious "just keep walking, friend", or even a hostile "go someplace - ANY PLACE - else but here".
I'm fairly certain that the original "иди своей дорогой сталкер" line was meant to express "don't be loitering around here and get moving to wherever you have to go". The tone it was said in also implied it was somewhat of a warning, or a command, rather than a threat like what the English translation did.