Well, somebody was being beaten, and then... shot in the end. A case of someone being murdered in the street (and just near my home. But... I think we can say that "everyone" is OK). Strangely, my mom heard nothing. It happenned 04:30 AM (Yeah, I woke up because of those noises and screams). I doubt it was a dream, most because of the "Bang!" part. Besides, my place lacks security.
Witnessing a crime is always scary. Even if the victim is unknown to you, it's hard to ignore what's happened. Crime is hardly impersonal; for those who have the good fortune of living in affluent neighborhoods, crime is little more than a story from a distant land that only happens to "them." They don't notice the unsavory business that happens behind their backs in the confines of nice suburban homes. When you live in an area like yours, sometimes you feel like you can never be safe.
I'm sure you probably know this already, but one of the best defensive techniques you can employ is avoidance. It's much easier and sometimes works better than any self-defense weapon you can buy. Walk confidently, know where you're going, be aware of your surroundings, and above all, don't appear nervous. Maintain a strong posture, keep your head up, and look straight forward. Travel in groups if possible. People are much less likely to bother you when you 1) travel in packs, or 2) look like you know the area.
I hope you stay safe and don't let this get to you.