Some smart AIs are aware of how their rampancy could compromise their current objectives or missions. Thus would follow this protocol accordingly to ensure that they would not allow their own rampancy to compromise the mission or the lives of those that are involved.
Smart AI Serina followed this protocol when her lifespan was coming to an end. Getting assistance from UNSC personnel on board the UNSC Spirit of Fire, she decommissioned her self. Not before leaving the crew with a goodbye message.