Nick of Time - S2-E7
Continuity mistake: After dodging the vehicles in the street, Don notices the time as 3 o'clock, when the machine predicted something would happen. When they go back into the diner, his watch has the time as 10:10.
Nick of Time - S2-E7
Continuity mistake: Don Carter is holding a glass of water at the lunch counter. When the shot cuts to him and Pat, his hands are clasped together, empty.
Nick of Time - S2-E7
Continuity mistake: As Don and Pat leave the diner and another couple enters, there are two glasses of tea that have changed position on the table with the Mystic Seer, and two chairs have suddenly materialized at the booth they were using when the other couple arrive to use the Mystic Seer machine.
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.