Prudie's response is right, I think, giving the writer, who is clearly disturbed by what's going on, an extra kick in the pants to make the necessary phone call. But there's one thing in her response that stands out as odd to me. See if you can find it:
I am concerned about an ongoing situation involving my next-door neighbors. My wife and I moved into our apartment about six months ago. Not long after moving in, we were alarmed to hear our next-door neighbors, a married couple with whom we share a wall, shouting very loudly at each other during a heated fight. Since then, the arguments have continued with great frequency, and the language from him is so loud and abusive that we are now starting to feel as if we should call the police, especially because they have a baby, and we sometimes hear crashing sounds. But if we call the police, they will know that it was either we who called or their other next-door neighbors (there are only a few apartments in the building), and I don't want that lunatic coming after us. When is it time to call in help?
Now is the time to call. Once, years ago, I lived below a similarly abusive husband, who regularly screamed vile things. One day, I heard the wife come home, cry out, and fall to the floor, which was followed by her hysterical sobs. I feared she had been attacked by an intruder, so I called the police. They came and left, and when I called the station to find out what happened, I was told: "It was nothing. Just a domestic." The couple went on to have a baby and move away, and I've sometimes wondered about that miserable little family. Fortunately, today there's a different attitude about "Just a domestic." Your call doesn't mean he'll stop, or that she'll leave him, but it does put them in the system and him on notice. You can call anonymously. And if you later feel in any way threatened by him, immediately make a follow-up call to the police.
Do you see it? "I feared she had been attacked by an intruder, so I called the police." Really, Prudence? After hearing this going on above you for weeks, months, whatever, when the screaming escalated to violence, your first thought was, "Must be a robber"? I don't buy it. Which makes me wonder why she felt compelled to say that. It sounds like she's trying to justify her decision to call the police (if she'd known there was no intruder, she wouldn't have called?), which is odd, since the point of her response is to convince the ambivalent writer to make the call, not let it go. Weird.