Well I think it all boils down to what makes the most. Sounds like having a union is more beneficial to you monetarily, and then you benefit from having a union in future disputes as well.
I'm sure it works different in the States in terms of striking, and I don't know how it works for health care professionals here. But I'm a police officer, also essential, and we can't strike but other forces can. Obviously they can't walk off the job, but because they are unionized they can strike in their own way. For Example in Montreal they will strike by going to work with pajama pants on....yah, looks pretty silly, with a vest and gun on too, but let me tell you they deal with things quickly. Us...they take their sweet time, like our previous raise that was frozen. But we have no recourse really, other than SRRs arguing with them.