Best advice I have is can the union. I haven't seen one that ultimately helped. They create a bunch of inflexible rules that does little to benefit the worker and nothing for patients at all. If you need a union where you work find some where else to work. I see ads for medic jobs all over the country. If your employer doesn't treat employees with respect and a competitive wage there are others that do.
Without employees they will not stay in business too long. Ask the supervisor how many 24 hrs shifts in a row he can handle on the front line.