Would it be a hassle to let passengers off the plane, to walk across the apron and enter the terminal through some random door?
Hassle? Needs some definition as for whom. To spring this on ground staff would not be a good thing ... think of the strength of ill-feeling when deplaning FR passengers cannot access the terminal at STN as a starting point.
to walk across the apron - depends on the distance and any taxying aircraft or other moving vehicles ... could cause delay or put lives at risk ... and what about any disabled passengers on the aircraft?
enter the terminal through some random door - contamination between incoming and outgoing passengers possible, who has the key and who controls the movement of 150+ passengers? Not a good spontaneous idea.
Everyone needs to understand that there's a world of difference between "we can't do that," and "we can't do that without busting some paper-pusher's rule and making a little extra work for ourselves."
Understood but this is not a good spontaneous move, especially as the individual concerned seems to have health and lifestyle problems.