The court said that it had to be a competent adult person who clearly consents, and the waiting period, as you rightly say, is a help in being sure that we have a competent adult person and—something like the Quebec act—having a second physician interview the patient and form his or her view as to their competence.
I think part of your task is to figure out safeguards that would prevent a transient bout of depression from turning into a physician-assisted death.