Stupidity: All castaways knew about the highly potent drinks, but they each drank it all instead of just pretending to drink with fake sips each time Lord Beasley took a sip - thus knocking every one of the castaways out cold and losing another rescue.
Stupidity: After Eva Grubb first arrives on the island and states her frustrations to the castaways, she walks away and the Professor reveals a plan to not leave her in her current condition and have a boat sent back for her to get her some help. How is he going to do this? If he could contact civilization to get Eva a boat, then how come he could never do the same to get themselves rescued? Furthermore, how would he be able to contact anyone to help Eva anyway?
Suggested correction: You completely misunderstood his plan and the episode up to that point. Eva arrived by boat and ended up giving the boat key to the group. The group was going to leave the island on Eva's boat, but she wanted to stay and wouldn't go with them. But in his opinion, she was too emotional to stay on the island alone, so after they got back home, using Eva's boat, the group would find help and that help would go back to the island to bring Eva home.
