Character mistake: There are some musicians at different times in the movie. One of them is playing a moraharpa (traditional Swedish instrument, a predecessor of the nyckelharpa), but holding and playing it incorrectly. (00:38:37 - 01:39:45)
Character mistake: Daphne's mother is the one who pressed her husband to tell her the truth, but she is cheering when he says about the basketball anecdote that it was 'real', when later he corrects himself saying "real-ly me, disguised as a mascot." (00:17:25)
Character mistake: The first victim gets smacked in the face by the Mistress, and then in subservient fashion holds her hand and kisses it asking if she hurt her hand hitting him. Thing is, she slapped him with the right hand and he is kissing the left better. (00:01:40)
Character mistake: Zeke makes the bold claim that "John Kramer didn't target cops." This is completely and utterly false, and a cop like him should know better. Kramer repeatedly targeted cops. In fact, both "Saw II" and "Saw IV" have officers (Detective Mathews and SWAT Commander Rigg) as Kramer's main target.
Character mistake: During their bickering about the coffee, the idea is that the officers just drank some coffee made from beans coming from excrements of rhesus macaque. That's how the civet coffee is made; macaques merely chew and spit the beans, they do not 'process' them (that'd be the kopi luwak that he references immediately after). (00:27:00)
Character mistake: David Dastmalchian is the Polka-Dot Man, hyphenated in the comics, and in the end credits of the movie. Then again, when Waller threatens to kill everyone off, the name of the character appears in print as Polka Dot Man, no hyphen. (01:49:40)
Character mistake: A detective (Briggs?) told Sonny, " that I was stupid enough to believe your dark fantasy NINE-ELEVEN call." [emphasis added] An American law enforcement officer, in particular, should know and use "nine-one-one" (911) when referring to the nationwide emergency telephone number. "Nine-eleven" (written 9/11 and NOT 911) is used to refer to the September eleventh (9/11/01) terrorist attacks in the U.S. (01:15:57)
Character mistake: When David Frost interviews the fictional actor Bryan Martin, he adds a last question to the interview saying "before you go" and acts as if the guest is not gonna stay (as it often happens in talk shows, when some guests, especially the more famous ones, leave after their bit is over). However Martin is staying and in fact there is a special mystery guest a bit later that makes sense only if he is in fact staying. (00:02:00)
Character mistake: The prosecuting attorney told William, "In the interests of getting this thug [Danny] off the streets as soon as possible, his attorney has agreed to plead guilty to assaulting an officer, possession with the intent to distribute, and resisting arrest, and that's all in addition to his parole violations. We're looking at five to seven [years in prison]." The parole violations alone are sufficient to get Danny off the streets immediately. (00:09:34)
Character mistake: The patrol officer who stopped Will for speeding fired two warning shots in the air when Will ran. Patrol officers should not (and generally do not) fire "warning shots." (00:49:57)
Character mistake: Mia's Sea-Monkey, in a vertical position, was shown sinking to the bottom the jar. It isn't clear if the Sea-Monkey was dead or if Mia was referring to it when she said, "She's gonna freeze to death, Aiden", but Mia should have known how to properly care for her Sea-Monkey (or refer to the instructions) and, realizing the room was too cold, should have done something - such as wrapped a towel/blanket around the jar and/or moved the jar to a warmer location (e.g, near the fireplace). (01:22:33)
Character mistake: Doreen/Mom told Rose she'd be back from the store "in a jiffy." Rose asked, "How long is a 'jiffy'?" and Doreen replied "in about an hour." "Jiffy" typically means VERY fast (perhaps as short as a nanosecond) and, even if people have different perceptions of how much time a "jiffy" is, an hour is excessive by general standards and does not reflect its true meaning. (00:32:50)
Character mistake: Over the phone, Julie told her sister Sara, " I got them [parents] a bouquet", pronouncing the "T" in bouquet. Bouquet has French origin so the "T" is silent. Bouquet is properly pronounced like bow-kay (American English) or boo-kay (British English). (00:00:55)
Character mistake: When Tony is talking to the Biancis and others, he refers to victim Kevin Turner as "Kevin Grant" at least two times. (00:44:50 - 00:46:27)
Character mistake: After Clinton's phone call, Christine talks with her assistant and making fun of the "mourning", she says "We went directly to Streisand's opening at the Sands right from the cemetery." However, in Vegas Barbra Streisand never performed at the Sands; she did the International (then Hilton) and the Riviera. (00:05:15)
Character mistake: The end credits (which are also IMDb's source) have the protagonist as "Detective Lucas Boyd." However, in the movie, his name (see the nametag on his desk) is spelled "Lukas" with a K. (01:01:05)
Character mistake: Cynthia Kellogg comes forward to voluntarily give information about the James Urbanski case. Detective Nealy tells Kellogg, "As a matter of procedure, I have to inform you of your rights." Kellogg says she didn't do anything so doesn't need a lawyer. Nealy replies, "This is your right" and proceeds to inform her of her Miranda Rights. Miranda warnings are applicable to suspects/defendants who are in police custody (under arrest) and about to be interrogated, not voluntary witnesses. (00:03:02 - 00:03:57)
Character mistake: The end credits list one of the songs as "Score from Un Poste Al Sole." It is a misspelling. It refers to something played by the hotel TV inside Margaret's room, an Italian soap opera called "Un posto al sole," with an "o." (01:59:25)
Character mistake: Heidi Heatherley is referred to and addressed more than once as Dame Heatherley. Dames (and knights) take the title before the first name, so she should be Dame Heidi. It is surprising that a journalist, in particular, would not know this.