Awkward dialouge

Was just watching this tonight. I was quite impressed - it was very slowly paced, but also atmospheric, moody and generally well acted. However I had an issue with the dialogue at times, particularly the timing. Some of the responses came too quickly... if you're going to aim for realism, generally in reality, the answer doesn't coming immediately out of your mouth directly after the question. In one scene, during the interrogation of the school teacher, detective Bridget yells "Dan... stop!" to which he responds with "what?!" This seemed kind of like an unnatural response to me.

The sister's ballet performance in the hall also bothered me. Why would the dad engage in such a confrontation or display of emotion in front of everyone when he could have very easily stepped outside to speak to the detectives? I understand he was probably taken by the heat of the moment, but it's yet another moment that sort of rang false for me.

Oh well. I was pleasantly surprised by this and will overlook the (mostly) minor flaws. Gibney is marvellous.