If I must embody evil to do good, then so be it. 

We put them in a football field sized greenhouse. They are at one end, and a pool if water is at the other. They are inside a cage, surrounded by boxes that are being slightly agitated by rotors. We explain that they are about to be released at the same time as 1,000,000 wasps that are being pissed off in those boxes. At the 50 yard line is a snorkel so they can jump into the pool and hide from the wasps. It has a wire mesh over the top to keep the wasps out so they will be safe once they make it. 

The buzzer sounds and the gates open. They run, the wasps are on them like a flies on shit. They push themselves to the limit and then they see it. The snorkel. It's bright blue against the grass. They dip, grab it, slide a bit but regain their footing and take off toward the pool. They reach the edge, the wasps are right on them. They take a deep breath, put the snorkel in their mouth and drop in. The water replaces the feeling of tiny feet and the cooling sensation soothes the stings they received. They push out some air as they position themselves using a ladder. They finally feel it. The snorkel exits the water and the air leaves freely. A feeling of calm safety washes over them and they inhale a deep relieved breath... And something else. Suddenly, it hits them. The mesh that was made to keep 1 million wasps out of the snorkel was also there to keep 1 horsefly in.