Everyone is going to die one day. So "if" the head nun dies one day doesn't make any sense - "when" the head nun dies makes more sense.
Rosemary and I have occasionally thought about what might be possible options for us in that case, but we kind of put it aside, because it's not the reality yet. Rosemary and I might die before the head nun dies. There's no guarantee that the head nun will die before we do.
We reflect on death. We consider that if she does happen to die before us, then we will have to see who is in charge. We will have to take it one step at a time. If they want us to stay, if they want us to leave, then that's fine, no problem. Anything can happen.
There is a caution in planning too much. There is a caution in getting caught up in thoughts of, "Well what if this, and what if that". It's fine to think about some future possibilities in the sense of making various plans, but this is a plan that might be tomorrow, or it might be in ten years, we don't know. And when it actually comes, it might actually be easier to determine what to do. Trying to figure out all the different scenarios of possibilities could be endless and it could be a complete waste of time.