Maybe I'll start, and others can add to it.
The law is designed to respond to the overall circumstance of someone who is on the passage towards death. It is not designed to respond to a situation that changed someone's life circumstance after an accident, or where they get a diagnosis of some sort that changes their life circumstance. It's the totality of the four elements together. It may be the case that someone with a condition that is not otherwise going to end their life is suffering for other reasons and has another condition that is impairing them and has, therefore, put them on the path towards death. It's not an a) or a b) or a c). It's all of them together in the totality of the circumstances. An individual, whether or not they have a condition that is labelled as “terminal” but is dying of another condition and suffering from a third completely separate condition, in the totality of their circumstances, could be found to be in a situation where their death, to quote the bill, “has become reasonably foreseeable”, and qualify for medical assistance in dying.
Therefore, in that sense, it isn't meant to be categorical, but meant to be the totality of the circumstances involving all of those considerations.