I would imagine there is a contingency plan for if the surgeon becomes incapacitated, eg has an aneurysm/heart attack, so they’d probably do whatever that is
Probably something like palliative care until an on call surgeon can come in and finish out whatever was going on
Palliative just means relieving symptoms without dealing with the cause of the condition. In this example they might administer medication to lower a spiking heart rate without dealing with the obvious causal factor of the unfinished surgery bc they are not qualified to do so. This would be palliative in nature.
That said “palliative care” is a sub speciality in its own right as you describe