I'm afraid sometimes healthcare workers DO close ranks. Have seen it at first hand - thankfully not when I've been a patient but have seen it when working with doctors and it's not pretty. (It happens with nurses, too, and I'm sure other disciplines.) I'm a health journalist by background, and I've listened to some appalling stories from people who have been very badly treated - stories that were backed up by documentary evidence, other witnesses, and later confirmed by official inquiries. Some of those people were patients, some were doctors, nurses and other NHS staff who had tried to raise concerns properly, by the formal route, and been victimised as a result.
See Mind's Death by Indifference reports if you really want to be horrified. Terrible thing is that there have been two DBI reports now - all the shock and horror and promises of change by the people in charge have resulted in entirely insufficient action.
In fact I'm currently aware of a case of a nurse who dared to raise concerns and has been well-nigh hounded out of the profession as a result. The only reason she's just about clinging on is that she happened to have one senior colleague who thought the backlash against her was outrageous, and happened to meet someone who has long experience of fighting injustice and decided to help. But even now the nurse has been cleared and it's blindingly obvious to the authorities that the whole thing has been a ridiculous charade, the bastards are still trying to make her life so difficult she'll give up.