And next here tonight some thrill seekers got a little more thrill than they bargained for when a swinging roller coaster called the ninja derailed. Almost two dozen people dangled for hours last... See More
And next here tonight some thrill seekers got a little more thrill than they bargained for when a swinging roller coaster called the ninja derailed. Almost two dozen people dangled for hours last night and ABC's Cecilia Vega has what to tell yourself if something goes wrong. Reporter: What a terrifying ride it was for the 22 people trapped for nearly three hours on the ninja. Incoming units to magic mountain. We still have victims on the ride. Reporter: There they were on this suspended, swinging roller coaster, hanging from a track, dangling precariously above the ground waiting for help to arrive. This is going to be challenging. Reporter: An entire tree fell on the tracks, derailing the first car. See that white metal arm? It's supposed to be attached to that red railing. Firefighters struggled to reach riders that high in the air, having to lift them to safety one by one. Four went to the hospital. We saw the ninja go into the trees and it was cracking noises and crashing noises and a lot of screaming. Reporter: Today workers were on the ride inspecting the tracks. Statistics show accidents at amusement parks are extremely rare, and this time there were only minor injuries. But just last year, a woman fell to her death from a roller coaster at a six flags park in Texas. The ninja may be known as the black belt of amusement park roller coasters pro. ING 4g turns and 55-mile-per-hour speeds but experts say if a ride goes wrong, just wait there until authorities give instructions. Follow directions and most importantly, stay calm. The worst thing you can do is panic. People start to decide they're going to get out. They need to get off. The best thing that you can do is remain calm. Reporter: Six flags said in a statement safety for guests and employees is the number one priority. The park is open today, but, Diane, that ride, the ninja remains closed for inspection. Great, Cecilia, thanks for reporting in tonight.
This transcript has been automatically generated and may not be 100% accurate.