Ivan's first sign of betrayal: oozing Rita's mouth shut. Even Zedd praised him briefly for that.
Dulcea appearing and taking out the Tengu Warriors.
Fred, who'd been spying on Ivan Ooze for a good part of the movie, revealing to the kids of Angel Grove that Ivan has ordered their parents to take a fatal dive at the construction site and convincing them to go help him intervene. The kids eventually make it to the site just as their parents are approaching a steep drop and start pushing them back—however, many of the kids aren't strong enough to stall the adults, so Fred, Bulk, and Skull commandeer a nearby high-pressure water cannon to buy them some time. They manage to last until the Power Rangers finally defeat Ivan, breaking his hold over their parents.
On a related note, Tommy gets a moment near the end when he uses his Zord to bridge the gap in the monorail track that Ivan destroyed a part of, saving the kids using it from a fall.