Not really freight, but............
DC-8 pax charter, middle of winter in Philly going down to the islands. Just prior to push back, my then girlfriend FA comes to the cockpit and says there is some strange thumping noise all the way in the back. Capt. wouldn't have it, but after several minutes talked him into checking. A loader had fallen asleep on some bags and the other guys had closed the door, not knowing he remained inside. Poor chap was in a panic obviously as his hands were bloodied from all the 'thumping'.