Perhaps nobody will die! I'd quite like that Dr Perfect is injured and recuperating and a new doctor (maybe a woman or a South Asian) replaces him in the practice, and isn't all touchy-feely, in tune with the area. And they all hate his/her unsentimental ways until they come to realise that he/she is great: a bit like Nurse Crane when she arrived.
For Sr Julienne to die would be quite a departure from RL and I wonder if they'd do that? It would be easy to ship her off to the Mother House if JA wants written out: Mother Mildred has a dark night of the soul and Sr Julienne has to take over, for example.
I was also wondering about Young Tim. Since he apparently goes off (distraught and guilty) to join the search party and the actor might, at the age he is at, want out. But again, it seems a bit drastic. They could easily just make him invisible! Timothy's staying at uni for work experience, gone to volunteer in Africa for his holidays, etc.
I actually wonder if they have tried to foreshadow it a bit - does anyone remember the train shaking the walls when Cyril went to see the flat with Fred? I thought it was supposed to be like, oh the poor Robinsons, having to live so close to the trains (lol... our house shakes when the pendolinos out of Euston go past - we frequently have to reassure visitors that there isn't an earthquake...) but perhaps not?