There are quite a few specialist areas, that you would need training for. In depth knowledge of motors and motor controls, HVAC systems, large boiler controls, IT system distribution. fire alarm, call systems, Building management systems, PA/PE safety earthing systems in designated medical rooms. Fault finding experience, is an absolute Must!!
....Lot's more really, but i think you'll see, a lot more involved than simple domestic/commercial installations...
Anyone can adapt if they want to, just depends on how interested you are in what your doing. It is an interesting area, you won't find much else out there that covers the scope of work you'll find in a modern hospital...