The End of Time: Part 3 - S1-E40
Question: Why did Gluto decide to freeze himself?
Other mistake: In this episode, Eric tries to destroy a mutant, apparently unaware that Rangers don't destroy mutants but freeze them. Yet in Quantum Quest and Clash for Control, he froze a mutant.
Eric Myers: Quantum Power.
Trivia: Ransik doesn't speak a single line in this episode.
Answer: Gluto has quite a cowardly personality and never contributed too much in fighting against the Power Rangers. When he felt that the final battle was getting too intense for him, he decided that he would rather be frozen than participate.