There you go again.
If someone is not with you they are having an 'extreme and emotional reaction', have an 'unresolved issue', 'didn't like' what you wrote earlier, 'very hostile', 'jumping to conclusions', 'simply don't understand the issue' -- and that's just from this page.
You are coming across as a human tank.
If someone shows up in an emergency room bleeding and unconscious from an accident, do the surgeons wait until the patient is able to give consent before treatment?
Even in the case of your DSS needing an emergency appendectomy or with a broken leg, I would sincerely hope that your main focus would be the child himself in that situation and not the complicated antagonisms among the 'adults' involved here.
What is to be gained in the case of a medical emergency from a situation where the mum and you are fighting about treatment options or visitation (which I have every confidence would happen given your demeanour on this thread and your description of the mother's personality) with you and your PRs and the mother and her identical rights battling it out from the pov of your respective prerogatives, neither one willing to give an inch? If the mother tried to give her son any kind of grief while he was hospitalised for any reason and she visited, she would be turfed out or told to behave herself by the staff.
The child has a father, who is capable of being contacted no matter where he goes, since we now live in the age of mobile phones, in case of emergency.
The only guaranteed result of persisting with the joint residency order (and not confining it to the child's father, with him then according you legal in loco parentis rights) is continued antagonism between you and the mother, and this is 100% guaranteed to work against the best interests of the child. This mother has already shown that she is willing and able to take out her feelings on her child, and yet by raising the stakes involved, you are contemplating raising the heat of the proceedings considerably. I think you are locked into a conflict with the mother here, from which I fear you will not back down due to extreme stubbornness and pigheadedness, with the potential for enormous collateral damage to the child and his relationship with his mother.
When you can focus in such a blinkered fashion on your rights, a list of PRs on a piece of paper, you can't blame anyone else for focusing on those rights too. You have caused this situation to develop by your insistence on the joint residency, and the child you profess to care so much about has already been wounded by the consequent flak from his mother. You know what this woman is capable of, yet you are going to keep on provoking her? Is your aim here the complete severing of the child's ties to her? He expressed his deep emotional reaction after the last episode with her because he cares about his relationship with his mother no matter how she treats him.