onCitiesSlide: function(e) {
  travel.updateStationsPos();
if (this.isFactsEventRunning()) {
    merlin.act();
  } else {
    ...
    merlin.update({ "fact": fact, "city": city });
    this.finishCityEvent(fact);
  }
}
...
finishCityEvent: function(fact) {
  ...
  if (!!fact && nextSlideNum != currSlideNum) {
    facts_gallery.slideToFact(nextSlideNum);
  } else {
    merlin.act();
  }
}