Yes, I agree with everything you mentioned here. Once you have a union job, it's very difficult to get fired, within reason. And Proctor's conduct was not within reason as far as his employment was concerned.
It sounds like Yuri will now be working in a training/instructing department IIUC. I can't imagine he was demoted or took a pay cut, since the only discipline he received from the Proctor fiasco was him losing vacation days. Yes, he might lose some overtime opportunities, but even that is hard to say, depending on how short-staffed they might be.
IMO, I'd think he'd be pretty tired of the bureaucracy surrounding front line work, especially after everything that occurred which he obviously didn't agree with considering his praise of Proctor. Also, I imagine they brought in sweeping changes and oversight to the Troopers' roles/authority when all was said and done. I imagine none of them would want such oversight since it seemed they pretty much had free rein to do whatever they pleased previously (such as drinking in bars with co-workers while on duty with your police vehicle). Having their freedom taken away would be hard to swallow. Easier to just apply for a different job/location and start fresh.
MOO