Five Characters in Search of an Exit - S3-E14
Factual error: When all 5 prisoners stand on each other's shoulders with the ballerina on top, she still can't reach the edge of the cylinder. But when just the 4 men do the same thing and the major throws his rope over the edge, he is somehow far closer to the top than he should be. He ought to be the ballerina's height and then some away - but he isn't. (00:21:30)
Answer: It's explained in the episode. The aliens are experimenting to see how humans react to various scenarios. This just happens to involve them using super strength.
Thanks. It's been a long time since I saw the episode so I forgot.