Have just skimmed most of the messages in this thread, so apologies if I've misunderstood.
IMO, the main difference between schools and the NHS is accountability. In schools, safeguarding concerns are usually about the child's parents or caregivers. Teachers are "encouraged" to proactively report issues because not doing so would have worse repercussions for them personally.
Worst case scenario, in a school, the teacher reports a "safe" parent, the matter is investigated (by social workers or the police) and closed with no further action required. In this case, the teacher is deemed to have done their duty and would likely be told that they did the right thing to report their concerns. Conversely, if there were safeguarding concerns and the teacher did not report it, there would be questions over why and how they didn't notice.
In the NHS, IMO, there is likely to be a culture of denying accountability (especially amongst management), subconsciously so, even if no-one admits it. Workers with safeguarding concerns about their own colleagues, or the service they provide, would essentially be "whistleblowing". They may be seen as a troublemaker (by management) rather than someone who was trying to save patients or improve the service.