This is one of the better episode's of the series. There a few humorous scenes and lots of great action.
One great humorous moment is when Gadget chases Brain toward the jungle, thinking he is a hula girl. As Brain runs he strips off his disguise. Gadget, wanting to return the hula girl's clothes, hides his eyes and continues to follow. The prophet MAD agent was an interesting character, with his long white beard and mesmerizing yellow and red eyes. Gadget, as he does with every MAD agent, causes him plenty of grief while unknowingly helping him detonate the bomb in the volcano.
The prophet MAD agent actually succeeds in getting Gadget near a smaller volcano as it erupts. Gadget stands at the mouth of the volcano, but somehow he survives the blast.
At the beginning of the episode, Gadget is chased by a mechanical shark. I thought that this would happen again later, but it does not. It's probably good that the writer's decided against that, because it would have been too similar to the Lake Monster episode.
During the lesson at the end of the episode, Gadget actually uses a Maxwell Smart line. After falling off a ladder, he says, "Would you believe ... I was practicing my swan dive?"