Trivia: Someone asked: Has anyone EVER figured out the math to that damn water-in-a-bottle-diffuse-the-bomb riddle? I actually have, in case anyone's wondering about it. If I remember right, they've got a 5, a 3, and they need 4. Fill the five, tip it into the 3, leaving 2. Empty out the three, and put the 2 in it. Then fill the five, and use that jug to fill up the remainder of the 3, which will leave 4 in the 5 gallon jug. Another possible way to do this: You fill up the 3 and tip these three gallons into the 5. Then you fill up the 3 and use this to fill up the 5. This leaves you with one in the 3 and five in the 5. Then you empty the 5 and tip the one from the 3 over, then fill up the 3. Then you've got three in the 3 and one in the 5. After you've tipped over the three this will leave you with four in the 5.
Trivia: When John is asked what he has done during his suspension from the police force he says "smoking cigarettes and watching Captain Kangaroo." This is a line he sings from the song "Flowers on the Wall" by the Statler Bros from the radio in Pulp Fiction just before he ran over Wallace. Appropriate, since Pulp Fiction falls neatly between Die Hard 2 and 3.
Trivia: In the German version of the first 'Die Hard' movie, the terrorists were changed into radical Irish because the dubbing producers didn't want to have German terrorists (see 'Die Hard' Trivia). In the German dubbing of this movie, however, they have decided to adapt the original background after all, and the late terrorist leader is called by his original name, Hans Gruber.
Trivia: The original ending of the movie was that Simon would get away with the gold, and McClane fired as a result of his failure. McClane would track Simon down and challenge him to a game called "McClane says", where an RPG without sights would be placed in the middle of their table, and every time Simon answered correctly, the RPG would be turned around, but it wouldn't be known who it was pointing at. Eventually, McClane wins and kills Simon (while wearing body armour that would protect him if the RPG hit him anyway). This was rejected because it would have shown a darker, revenge-driven side of McClane that the filmmakers didn't want. Another ending was also proposed, where McClane would re-arm the water jug bomb and place it on Simon's escape boat. When Simon found the bomb, the movie would end on a darkly comic note as he asked everyone if they had a 4-gallon jug.
Trivia: Screenwriter Jonathan Hensleigh was interviewed by the FBI because of the detail in his script. They wanted to know how he knew so much about the Federal Reserve, the connected subway spur, aqueduct, etc. He simply told them the truth - the Federal Reserve let him look around as research. They showed him the plans, told him about the subway spur, and the aqueduct was mentioned in a magazine. He was worried they were going to arrest him at first, but they ended up telling him that the plan in the film was actually feasible, and made changes to ensure it wouldn't work in future.