weird audio bug

var Sfx = function() {
  this.sounds = {}
  this.active = false
  this.max = 12
  this.playing = 0
}

Sfx.prototype = {
  init: function() {
    this.active = true
  }
  
, add: function(category, snd) {
    if (!this.active) return
    
    if (typeof this.sounds[category] === 'undefined') {
      this.sounds[category] = []
    }
    
    var s = new Audio('/sfx/' + snd + '.ogg')
    
    this.sounds[category].push(s)
  }

, play: function(category, volume) {
    if (!this.active) return
    
    var self = this
      , rs = fisherYates(this.sounds[category])
      
    rs[0].play()
  }
}