Generally, when there's a potentially dangerous situation going down that involves the police, it's recommended that people stay out of the situation as much as possible. Despite that, people have a tendency to do anything but.
Maybe it's because we all secretly (or not-so-secretly) want to be a superhero, or maybe it's because we really like doing the right thing that much, but time and again we've seen examples of people putting themselves in incredibly dangerous situations when trouble arose. Sometimes they help apprehend a dangerous suspect, other times they try to save somebody without any thought for their own safety.
We should repeat right now that this is NOT what you should do if you find yourself in one of these situations. When danger arises, the best step is to get yourself to safety, call 911, and try to give the proper authorities as much information as you can in order to help out.
However, when one woman saw a suspect being chased by police officers and quickly staying ahead of them, she decided to offer up her assistance, and then disappeared into the night. Just like Batman.