You don't need to actually listen, you can look at the eyes above each pathway. Those that pulsate in and out faster are the correct path. Do that 5 times and you're through the purge event. That said, the spot you start in I've yet to see any fast-moving eyes so it might be hardcoded to all be 'incorrect'.

Of course, yeah the path is as far as I can tell random, and the most annoying part is that you have to react to the other event attendees so they don't push you away from the correct path as you look at the eyes.