I believe if you have witnessed a crime where someone has sustained injuries whether it be minor/life threatening and you are able to help you should. If you are able to but choose to video the incident instead or not try to help were possible you should also be liable and potentiality face charges.
You may be interested in these active petitions
There have been incidents including fatal attacks where instead of helping, people who witnessed the crime watched and even took videos, uploading them to social media. In some cases if they provided first aid instead they may have been able to save lives. I personally believe if you don’t help and are able to do so you should also potentially face charges depending upon the severity.