Character mistake: It is highly unlikely that the recipient of Mr. Butler's application for the professorship position would not only call him so soon, but ask him to come to her office right away (where she would humiliate him for the things he wrote in his essay on "qualities that make me a good teacher"). Moreover, her failure to listen to Mr. Butler and give due consideration to his assertion that someone else actually wrote those offensive things showed poor judgment, especially since she knew the person who referred Mr. Butler and spoke highly of him. Someone tampering with his application would make more sense than believing that Mr. Butler actually wrote those things that criticized the very college he was applying to and boasted so much about himself. That Mr. Butler was not able to say more to make his point believable is also problematic. He is an English teacher, so should have the vocabulary and mastering of techniques to make a convincing argument, but he failed to defend himself.
Character mistake: When discussing the new Pope's name (Luke) at the end of the film, Langdon says: "There have been many Marks and Johns, but never a Luke." In fact, though there have been 23 Pope Johns, there has only been one Pope Mark - reigning for 9 months in 336.
Character mistake: While he is describing his origin, Dr. Manhattan mentions a circulatory system appearing at a military base. However, what is actually shown is a nervous system, as it depicts a brain and spinal cord.
Character mistake: When Lt Gannon is in the dogfight with the Russian jets, he announces that he is deploying "chafe and flares." The term is spelled and pronounced "chaff", and any pilot would know that.
Character mistake: When Malloy first visits Frannie in her apartment, he says the girl was killed on the 15th, but when Frannie is in the cop car for the first time, Malloy's partner says it was the 11th.
Character mistake: Nick states that Wall Street was originally a wall (correct) built to defend against the British (incorrect). The original wall was a wooden palisade built in the 16th Century to defend the Dutch colonists against invading natives and to prevent livestock from wandering uptown.
Character mistake: Joan Clarke pronounces the name of the mathematician Euler to rhyme with "ruler", when in fact it is pronounced "oiler."
Character mistake: There is a misspelling on the cover of the issue of Forbes magazine shown in the presentation about Stark's life. It reads "Tony Stark takes reigns at 21". The correct spelling of the word is "reins". Stark may "reign" at Stark Industries but he would take over the "reins" of the company.
Character mistake: When Carolyn first addresses Imam, she quite obviously pronounces his name "ell-mom," as though the capital I in his title were a lower-case L. It should be pronounced "ee-mam". We distinctly hear Ali call out his name in this fashion after the ship crash lands on the planet.
Character mistake: The information on Walter's "patient information sheet" lists his address as 5962 Delco St but numerous shots indicate his house number is 238. (01:03:25)
Character mistake: An unloaded automatic pistol is much lighter and balanced differently than a loaded one. When McClane hands "Bill Clay" (Gruber) the empty pistol, a terrorist of Gruber's credentials should pick up on the odd balance (I notice that difference, and I very rarely even pick up a gun).
Suggested correction: This presumes that a person can notice the difference between a fully-loaded pistol versus a pistol that is empty, which makes sense. However, it would be much more difficult for a person to tell that a gun is completely empty versus one that only has one or two bullets loaded. Since Gruber has no way of knowing his ruse didn't work, he doesn't believe McClane would have given him a completely empty gun. He obviously believes there is at the very least one bullet in the gun. He's not planning on getting into a shootout with McClane, he is just planning to threaten him and he certainly doesn't need a fully loaded gun to do that.
Suggested correction: It's easy to tell the different between the weight of a loaded vs. unloaded pistol, but given Hans had never held the pistol before, he had no way to compare the weight. Unless he regularly handled that particular model of pistol (unlikely, given his pistol is a completely different make and model) he would have no point of reference.
Character mistake: After the first attempt by the kidnappers to get the ransom money, they tell the FBI to bring the money behind the Foo Chow restaurant. Clive gives Carter and Lee the exact same destination. Why in the world would kidnappers give the FBI a drop-off location exactly where they are based?
Character mistake: Close to the end, Madison is looking over the H.A.L.O. list on her laptop. When Dylan's profile pops up, her last name, Saunders, is misspelled as Sanders.
Character mistake: After the Congressman is killed, the killer dumps pills on the floor of the car. Then the car is then rolled into the river. At about 15:07 the news reporter mentions that the Congressman's heart pills were found in his lap. This would be impossible because the pills and bottle would float and the pills would dissolve in the water. (00:03:45 - 00:15:05)
Character mistake: Early in the movie Cary Grant is on the beach and is told he has a phone call. While conversing with Bertani, Cary Grant has the handset backwards - he is speaking into the earpiece and listening to the mouthpiece where the chord is attached.
Character mistake: The bank robbers send out a hostage and put a drawer around his neck with a note. The drawer is bugged and the bank robbers can monitor the police. The police just leave the drawer lying around on the table for half of the movie inside their mobile headquarters. This drawer should be in a forensic laboratory being checked for fingerprints and similar.
Character mistake: Near the end of the movie, John's wife calls one of his colleagues and says, "Jad, it's Laura, John needs a favour." Her character's name is Lara. (02:08:30)
Character mistake: Engine #1206 is instructed to take the nearest siding upon hearing the news of the oncoming train. Frank does the maths and determines that they will not fit into that siding. He states the siding being 4011 feet between signals, with about 2500 of actual usable space. Engine #1206 with 25 cars would only equal 1580 feet, giving them more than enough room to clear in the first available siding.The average length of a railroad car is 60 feet. Even if the cars were considered "long", total 25 cars would have fit into that siding.
Character mistake: Once Santino and Ares find John again in the hall of mirrors, John is fighting two of the grunt men that came in with Ares and kills them. Both of which had light assault rifles and weapons on them. John and Ares proceed to empty their pistols out at each other before she runs off with Santino. John then throws his empty pistol away and gets up to pursue his target unarmed and while limping. It is unreasonable to think that someone with his skill and training and experience would not take two seconds to reach down and pick up one of the guns dropped by the two men he just killed before chasing after his target, especially given the highly trained body guard with him accompanying his target. As well as probable encounters with more grunts. To add to this, he was seen doing just this moments before when he had limited ammo and each time he'd down a few enemies he would pick up one of their guns and continue. (01:41:30)
Character mistake: When the plane is speeding down the runway at the beginning, a female flight attendant is seen walking, and Kyle is seen buckling her seat belt. Everyone would have been sitting down and buckled in at this point.