To participate in a lethal injection is to occupy the medical role and use medical training for a purpose that is not part of the goals of medicine and that harms the recipient of treatment.
Julian Savulescu's writing on conscientious objection is guided by an emphasis on the principle of distributive justice that does not allow religion to have a special status as justification.
When a pregnant woman is knowingly causing harm to her unborn child, there are various legal interventions that can be taken to protect the rights if the fetus.