Yea so a few things he pointed out in this write up were readily observable. For example, the air falling out of the freezer is actually quite visible when hitting a hot humid ambient air. Also you could see the rate of defrosting accelerate everytime you opened the door.
By the time we were able to find a gas station with dry ice we were out looking for open wal marts at a 73 mile radius from the house (Columbus Texas). The dry ice was not significant enough to do much more than get the fish cool. It was too late.