What is the correct general priority sequence if you arrive first at a serious road traffic collision scene (and it is safe for you to help)?

1. Photograph the scene for social media, then move casualties immediately into the road
2. Protect the scene, make vehicles safe where possible, call emergency services, then assist casualties within your competence
3. Pull casualties out first regardless of fire risk, then call for help later
4. Leave without stopping if nobody you know is involved