The researcher then went on to explain that they haven’t, and won’t try it on any comatose-appearing patients? Why? It came down to the problem if the patient asks to die. The only way to avoid having to face the question…was to never do the thing allowing it to be asked.

That sucks, because if I was comatose with no expectation of ever recovering then dying would be high up there although having the ability to communicate would probably reduce that desire.