Years back I spent several decades working in a medical university and hospital. I designed an 'ambulatory I.C. room', and ran single circuit lines all over the place.
The rationale for single lines is this: Imagine one person on a respirator, and another person on a computer controlled auto-defibrillator, and etc. There must be no interaction between the circuits. There must be no computer supply noise or motor noise from one circuit bleeding across a shared neutral and getting into another computer operated machine. I have seen the electrical noise from an impact dot-matrix printer get into the UPS for a heart-monitoring system, and trip on the UPS until the battery ran down. I specified an isolation transformer to keep the utility equipment separate from the medical equipment.
In our E.M.G. lab, used for experiments, our high-impedance instrumentation amplifiers would pick up signals from commercial radio stations. I designed a Faraday room, experimented with three methods of grounding the screen walls. We eventually were able to keep the noise out, unless you opened the door three inches! Sorry, I diverge.
The OP question opened the door to recalling how one machine's noise could travel across the neutral and pass through a computer's power supply, to interrupt a computerized system. My example was the printer that tripped the UPS. It was an unexpected event, looking from the electrician's viewpoint. In designing within a medical scenario, we must look for the unexpected events and plan ahead.
That was years ago, and perhaps now, computer type equipment is better and quieter. It would be if I was still in that field.
