George Clooney learned to rappel out of a helicopter for this part. He found it "fun and weird and scary."
George Clooney was so starstruck by Armin Mueller-Stahl that he kept offering to get him coffee on set.
Unlike their characters, George Clooney and Nicole Kidman got along very well on and off the set. In fact, Clooney, a notorious prankster, never pulled a prank on Kidman, out of respect. Clooney became such good friends with Kidman and Michelle Pfeiffer (on the set of One Fine Day (1996)) that both put up a US$10,000 wager that Clooney, who had vowed to never marry again, would be married with children before turning 40. Clooney won the bet (although he did eventually get married at age 53).
The part removed from the bomb is called the "primary". This means that these bombs are thermonuclear bombs. The primary is a small nuclear bomb which is used to start the chain reaction in a much more powerful second bomb.