Firstly, I work in a non-union department, therefore I admit that I know diddly-squat about the how a firehall operates within that realm.
Secondly, being in an industrial setting with a private company, it is common place for the plant operators who serve as part time firefighters to refuse to perform certain tasks that they aren't comfortable doing. They use the excuse that "It's not safe". Our hands are tied. We're not allowed to force them to do anything against their will. This kind of thing is akin to having a boner & running into a brick wall. You know what's going to happen when you assign them, and there's nothing you can do.
I would say that 60-70% of the part time guys are only there because they get overtime for training. They're not in it for the right reasons.
So, that explains my answers. It's how I've had to work for 20+ years!