Titanium audio player stops playing mp3 after a moment

In my Titanium iOS app I'm using the Ti audio player:

var mp3URL = "http://www.noiseaddicts.com/samples/47.mp3";
 
var audioPlayer = Ti.Media.createAudioPlayer({ 
    url: mp3URL,
    allowBackground: true
});

When I click the Play button, it begins to play the clip (I can hear it, and it's correct), but then automatically stops a split-second later. I can replicate this 100% of the time and it always happens. I am not double-clicking the button or anything. Quick single click.

My full source code (excluding some of the UI stuff) for the audio piece is here.

I am using Titanium SDK 3.4.0 GA, targeting iPhone 4S (v. 8.0) with XCode 6.0.1.

Any ideas?