Fred: Okay, Ace? I get your arm working, you can do the rest yourself, right?
Johnny 5: Kay-O, Derf.
Johnny 5: That's what I said. Derf.
When Johnny is spinning the two robbers around, you can tell that he is actually holding dummies. In the close up shots of the robbers, you can see them kicking their legs, but in the wide shots of the room, they are rigid and lifeless.