I had similar thoughts. Someone more knowledgeable would probably call them “healthcare professionals”, or “healthcare practitioners”, not “doctors and nurses”.

And you’re right, as important as they are, they can’t do their jobs without the infrastructure you’re pointing out. Power and water are more essential, as they enable everyone all of the time. And waste piling up would create serious problems fairly quickly.

This reminds me of the Silo series, where every level thinks they keep the Silo running.