Random Scream...?
Near the end of the movie, when Max is revealed as the head vampire, there's a scream heard briefly in the distance. This happens at some point when Max is explaining his plans to Lucy. I could never figure out whose scream that was. Also,it seems as if Max is the only one who hears it - I seem to remember him tilting his head back as if he's trying to hear it better.
Was the scream just for dramatic effect or....what? It always struck me as a really bizarre moment.