It might be better if doctors could make hard choices like this and keep it absolutely secret, but it's nearly impossible to contrive. As long as most people strongly disapprove of that sort of action, and people who want to become doctors do not have overwhelmingly different inclinations, and the training itself does not explicitly advocate for that sort of action, the vast majority of doctors will not take the organ harvester side in the dilemma, even in circumstances where they think they can get away with it (which will be rare,) and those are the basic minimum requirements to pull it off without people guessing.

A society where the public didn't mind doctors harvesting the few to save the many would probably be considerably better off, but that would require the thoughts and actions of the entire society to be different, not just the doctors within it.

Following consequentialist ethics doesn't mean that you should behave as you would in the highest possible utility world, if that doesn't increase utility in the world in which you actually find yourself.