Brief description
After he has had his eyeballs replaced, John Anderton uses his old eyeball to get through the "Eye-dentity" retinal scan to enter his old workplace. As he gets the eyeballs out of the ziplock bag, they slip out of his hands and roll down the concrete corridor. One falls into a storm grate, and Anderton is just able to catch the second eyeball by the fleshy nerves and blood veins hanging off the back of it.
The scanner mistakes the eyeball for the whole body.