Hmmm, let me see..
They were spotted walking along the central reservation, officers of the highways agency were sent to stop them, the highways agency if I recall, have absolutely no powers to detain. On approaching, the sisters try to flee across the carriageway, and one of them is caught a glacing blow by a moving vehicle, at the side of the road, they both appear relatively calm. There was absolutely no reason to go out 'guns blazing' so to speak, to two women that look disoriented but passive.
It was only after the police arrived, and while the 'witness' was explaining what had happened so far, that Ursula decided to flee into the path of the truck, which shattered her legs as the truck rolled over her, and Sabina ran into the path of the golf.
There was no possible way that the police could have prevented that incident from occurring, unless you are an advocate of totalitarian policing, at which point, every person coming into contact with a police officer, will be arrested and detained until such a point as the officer can assertain that they are safe to be released.
After the initial impacts, you have an incident to deal with, and a minimal number of people to deal with it, two people, both involved in serious RTA's, the first thought is the duty of care, the preservation of life. Did those officers have ANY idea of what the injuries were? Beyond Ursula's compound fractures (obvious by the bones sticking out of her legs), there were no immediately visible injuries, that said, both were in a delerious/semi-conscious state.
At this time, while awaiting the arrival of paramedics, the duty of the police officers, was to close the entire carriageway, and make sure that the twins were kept in a stable condition, which they attempted to do.
Ursula, initially was the most conscious, as you can hear in the tapes, she was shouting quite loudly that 'they will take your organs'. Sabrina at this time, was semi conscious, and being attended to, only by one female officer, it was not expected, that somebody, that had just been hit by a car doing almost 70mph, would be able to do much of anything, and conventional wisdom dictates that when you go down, you stay down.
The screaming by her sister, that 'they will take your organs', very likely triggered an adrenaline fueled fight and flight response in sabina. There is not a police officer in the country, that would have expected her to have resisted the way she did, considering the impact she had just sustained, hence the comments about how they must be on something, that you hear in the tape. There is no other obvious explanation.
Robbie G, you are looking at this with the benefit of knowing exactly what happened next. That means that in this instance, you have a massive advantage over the officers at the scene. And if you think for one moment, that you would have reacted any differently to the officers at the scene, I suggest that you get off your keyboard warriors ass and prove that you are some sort of supercop.
As to why Sabina was released after being charged with assaulting a police officer, and trespass on the motorway. It is stated in the documentary, she was still semi-sedated when she received her first psychological evaluation, she appeared to be perfectly normal. And most importantly, the psychologist was not shown the footage of what happened. His assessment was made solely on what he could establish in a very short interview with her.
The system was at fault, there is no doubt about it, even the judge at the murder trial said so, and he handed her the punishment that he was mandated to give her, even though he was in favour of an 'until she is no longer a risk to the public' sentance, the same given to people like peter sutcliffe.
Ultimately, the officers on the scene, did nothing wrong, there was no way to predict the way events unfolded. And if you think you could have stopped it.. Can I have your lottery numbers, as I am sure you must win every week?