Your supervisor sounds like an ***.
With those nurses I have to fight the urge not to bang heads together (metaphorically of course) and remind people that we are here for the best care of the patient.
The way our ward is set up, we have thirteen general beds, another 3 beds that can be locked off for a high care area, and 3 seclusion beds. Usually patients are happy to be moved out of the high care area. As others have said, we would frame it as 'we need you to move, I get that you don't want to, however moving to the open ward is a good thing, its getting you closer to going home. This move is going to happen and I would much rather help you with it. I don't want to see things going backwards for you"
If the patient was to kick off, we would need to assess whether the patient could be managed on the open ward or needed to go back to the low stimulus/seclusion area and if need be gather a large team. It's amazing how often the presence of lots of burly security and pysch nurses helps encourage compliance. That sounds wrong like I'm out to intimidate, the best comparison I can offer is when a patient hasn't been able to pass urine and we start to gather the supplies to insert an IDC and all of a sudden the patient manages to pee