Die Hard has become one of the most popular movies of all time. It seems that pretty much everybody loves it. It does, however, have a few problems when it comes to storytelling, but one of them apparently does have an explanation, or at least it did, originally. The issue regards the scene where John McClane first encounters Hans Gruber face to face. Gruber pretends to be one of the hostages but McClane isn't fooled. But the question is, why not? How did John McClane know "Bill Clay" was one of the terrorists? The screenwriter says that McClane saw something that tipped him off, his timepiece.
When Bruce offers the cigarette to Alan Rickman, Bruce sees the watch. You see his eyes look at the watch. That's how he knows that he is one of the terrorists.
What does the watch have to do with anything? Well, it goes back to an earlier scene that ended up being cut from the film. Screenwriter Steve E. de Souza explained at a 30th-anniversary screening of The Running Man, covered by Slashfilm, that there was originally a scene at the beginning of the film where Hans Gruber and his team all synchronize their watches, and the audience sees that every one of them is wearing the exact same watch. As John McClane begins taking down the bad guys in the building, he notices this fact when searching the bodies, so when he sees Hans Gruber's watch, when handing him a cigarette, he knows he's dealing with another one.
The reason the earlier scene was cut reveals another interesting bit of trivia. Apparently, Steven E. de Souza only came up with the idea of having the thieves escape via ambulance in the last week of filming. As such, when the earlier scene with the watches was shot, there was clearly no ambulance in the back of the truck they arrived in. Cutting the watch scene meant cutting John McClane recognizing watches.
We never really get a clear shot of Hans' watch in the final version of the scene. One expects there was originally a close-up that showed us Bruce Willis noticing the watch that had to be taken out as it would have made no sense in the final cut of the movie.
So there's the solution to a mystery that perhaps you didn't even know existed. It turns out watches were once an even more important part of the film than we thought.