I think key splitting might be a better solution for the corner cases of unconscious or self-destructive patients. For example, split the key among 6 people as

I think key splitting might be a better solution for the corner cases of unconscious or self-destructive patients. For example, split the key among 6 people associated with the patient such that any 4 of them are sufficient to decrypt. That way, even if 1/3 of the key-holders are not available, you can still get the info. This still gives you protection against database dumps and the insider threat, while not completely eliminated, is vastly reduced.