The janitor's room at the Haagse Hogeschool was converted into an FBI instructor's office for the character played by Val Kilmer, with vintage old brown furniture, dark green lamp shades and old boxes as filing cabinets. This scene was ultimately cut from the theatrical release of the film.
The water title sequence at the start of the film was not originally filmed as the title sequence but as a flash back later in the film. After production was completed Renny Harlin re-edited the film numerous times, and the water flash back sequence was changed to a title sequence.
Towards the end of the movie, Sara and Gabe are standing on the beach as the helicopter approaches. It can be seen that they are standing very close to the water. In the next shot from the opposite side, they are suddenly standing at a considerable distance from the water.
When the team enters the main building on the island for the first time there is an overhead shot in which an entire sound crew holding a boom mic is visible on a balcony in the lower right-hand corner of the screen.
Lucas: When I was a kid I lost both my parents. Freak thing, ten years old- BANG. - mortality. So I grew up livin' real hard; racing cars, smoking, drinking, sleeping with any girl I could find... Real stupid, dangerous lifestyle... then I turned eleven
Why did Vince Sherman's gun keep switching from a Baretta 92F to a Glock 17?
Because this movie was very poorly edited. It is possible that there was significant amount of re-shooting done and for whatever reason, the prop gun used from the original shooting was no longer available, or nobody noticed that the gun was different for the re-shoots.