DEA touts drug disposal drives as reducing harm, especially if you get rid of your unused narcotic analgesics, but you could use them to reduce suffering in a natural or manmade disaster.
Medical professionals in particular should consider keeping unused opioids in their homes or even their vehicles. Of course they should lock them up or take other precautions to make sure they do not fall into the wrong hands.
Natural disasters like hurricanes, tornadoes and earthquakes can overwhelm emergency responders, leaving injured people to suffer in agony. If you have even a few pills, you can reduce the suffering until an ambulance arrives.
Remember the Boy Scout motto? Be Prepared. If you can do it legally, consider keeping those unused pills in a safe place.