Thanks for that; appearing when it did, and with the wording it has, it seemed to me to address the case where there is one - ie single - flight crew member on the flight deck who has become incapacitated, rather than two members, one of whom has become incapacitated.
I guess that with the ruling that two 'authorised personnel' must always be on the flight deck, the Part 26 Rule shuts down the potential hazard that one of them is incapacitated while the other cannot leave the controls, or indeed that one of them renders the other incapacitated in order to commit a crime.
It's a bad world we live in.