If you perform a role that you are not trained to carry out and the worst happens, you are the one left in the dock at either the Coroners or the Crown Court facing the charges not those by their actions who put you there.
Having given evidence in the past in a Coroners Court, I can tell you it’s an experience I never wish to repeat. After the incident (RTC) that occurred I was interviewed by the police as is usual, they said I was in no way at fault, and they were after the other driver (I had a cadet on board coming back from hospital at a weekend camp). 1 deceased one SI’d. Facing the barrister for the other driver was not an experience I wish to repeat.