David
Sadly, the driving issue is probably insurmountable. However, live saving isn't. I trained as a first aider & life saver in my teens (our Mum claimed she didn't care if my sister & I didn't pass our O levels [that dates us!] but did insist that we both did first aid & life saving), and have keep up my skills, through nurse training, serving as a Territorial Army Nursing Officer, working in many hopsitals, gaining BSc Marine Biology, then getting type 1 diabetes at 30 years of age, which meant I was no longer even allowed to drive minibuses professionally nor rejoin TA; I had to change direction a bit, gained MSc Environmental Technology (Health & the Environment), continued to go on expeditions to Arctic regions & Latin America, worked in public health, traval clinic, health research etc, assistant ranger at country park, orienteering coach, activity birthday party organiser, marshal on adventure races, mountain marathons & triathlons, compete in orienteering, ARs & MMs etc. I have steered clear of specialising in diabetes, as I share your views on prefereing to help a wider range of people.
So, best to do well what you are allowed to do. By the way, I have been involved in several first aid / life saving / resuscitation events, where I was able to do the right things until further help arrived.