Take an emergency device and a good first aid bag no matter how small the adventure is. 

I learned to always make judgement of the terrain on my own and also learned some practical tips by watching the trained people around me in action to help me in the situation. I would advise to keep up-skilling yourself and know basic first aid as it goes a long way to keep the injured person comfortable and alive while you wait for professional help. At the end it matters to keep everyone in the team safe even after the incident.