I would agree that 15 minutes should be the breaking point. My husband gets quite claustrophobic and anxious if he feels he is "trapped" . If Sp. Earth is moving at a normal pace or even quick stops its no problem at all, 25 minutes I think the anxiety would start to creep in, not to mention little kids that need to use the restroom. We were stuck on Dinosaur once, in a completely dark area of the ride, yet the vehicle kept bouncing around in the pitch black for a good 10 minutes. I thought he was going to lose it.