There's a reason that medical ethics in palliative care and hospice, as well as the law, prohibits the hastening of death. That's because there is often a strong motive to hasten death. No matter how painful the death process, for patient, family or healthcare providers alike, it's still prohibited in the U.S. to actively speed up, i.e. "hasten," the process with a medication. While we can't read minds, we can follow patterns, doses, and willingness (or refusal) to practice within a reasonable range of standards. We can also examples past history of behavior, ethics, judgement and motive.
That being said, my opinion doesn't mean anything. The jury will have the final word.