Factual error: At the end of the episode, Major General George Harper looks out the window, puzzled. As he looks out the window, we see a palm tree in front of the building that is facing the window. Reims, France, is in northern France, where it is too cold to support that kind of tree. (00:23:00)
Factual error: Decker is flying a Nieuport 28, which entered service in early 1918. However, the date is supposed to be March 5, 1917. Furthermore, the Nieuport was a French-built aircraft that was flown by the French and Americans but not the Royal Flying Corps.
Factual error: Decker speaks of Georges Guynemer's disappearance. Decker believes the date is March 5, 1917, but Guynemer disappeared on Sept. 11, 1917.
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.