Police?
Because 1) It's disturbing you and 2) If any abuse is happening, it may be an idea to get them involved.
Don't know if I would recommend that. Depending on what's happening when the police are called, well, bad things might happen. Bear in mind that when you call police on people who aren't expecting a visit from the police, the results can be... unexpected. Police don't know what's going on as they go in, the people inside obviously have no clue they are about to get an unexpected visit, and people might reach such as to produce unexpected outcomes, in a way that would be at cross-purposes with your goal of "helping". Depends on what the police of your locale are trained to do and allowed to do, but in my experience, the results can be... mixed.
If you just want them quiet merely appear at the door and make it clear that if things do not quiet down (or if you really want to help, say "If what I am hearing does not stop"), that your next step will be the police. The threat of police can be more helpful than the presence of police. If you really want to call, do it, but try to make sure police would help the situation and not add to the volatility.
Also personally I consider occasional thoughts of suicide to be a healthy part of an examined life. Thinking about it rationally is why I didn't do it. It's most dangerous when seen as a polite out, which it really isn't. It's literally a mortal offense against *everyone* you know. It's cowardly and maybe worst of all, lazy. There's so much good to be done, and crazy stuff to see, when you aren't afraid of death.
Not a huge fan of any of your logic to be honest. Like, about any of it at all. There is maybe one or two thoughts here that I don't strongly disagree with. But a lot of people seem to believe it, so oh well.