Let me put it this way; if an ambulance crashes then there are probably multiple external causes and effects that can result in the crash.
Not so much in a prison. Much more likely to be something internal rather than external that results in something going wrong.
And if NHS workers start ending up in ambulance crashes much more so than they did 20 years ago, regardless of the external rather than internal factors in this case, then wouldn't you think theres perhaps a problem? Faulty vehicles, inadequately trained staff? If so, who is responsible for that?