My first and likely most sensible people's first move would be to use a different hospital...
Hospital administrations can be no different than any other employer when it comes to in-house politics, manufacturing propaganda and have a standard 'place blame elsewhere' CYA response mode.
Funny thing is, when the middle management who did the administrators bidding by coercing the nurses to not organize into a union will find themselves out of a job. And 6~9 months afterwards the scabs (temp nurses) will be questioning themselves what the fūck did I get myself into. 🤣
