I think the quietude came across very well. In the beginning it's rather striking that there's no dialogue, given that they're playing and she's 4, but because the dialogue here is a given, it's almost like watching a silent movie, where you know the characters aren't actually mute, just that you can't hear it. And that works very well, especially as the focus transfers to Ed behind the window, because he may well not be able to hear them anyway. And I think that almost amplifies the content in other ways.