Medical emergency
Many countries have laws that require anyone to help those in immediate danger. Help can mean as little as alerting emergency services, or telling other people that the person is having a problem. People that know first aid are expected to help as much as they can.  Moving the victim to a safe place can sometimes do more harm than good, and should be left to people that know how to properly move injured people unless there is no alternative (for example, in wilderness first aid). Many states have laws that protect those helping.