Great question, and thanks for posting it on the forum!
You'll want to tackle this almost exactly like you do disabling a section (use a variable to track whether or not it has been played). The secret here is that you'll want to turn off Auto Play on the audio, and instead use actions to play (or not play) the audio.
The variable will default to false, so it will play the first time, and the second action will flip the variable to to true once the audio has ended. You can change the trigger to on page load, if you don't care if the audio has played through entirely once.