Character mistake: The protagonist says "You know, Croesus once said 'Count no man happy until the end is known'" but it's not Croesus uttering that line. According to Herodotus, Solon says it to King Croesus. (00:03:00)
Character mistake: A radio report refers to a character with two different police ranks with 15 seconds apart in the same broadcast - first as a Police Chief and a few seconds later as a Captain. (00:21:28)
Character mistake: Following the killing of a DEA forensics agent [guy sniped on the boat], a newspaper clipping is shown on screen. Underneath the headline of the article, "Assassinations" is misspelled from omitting an S in the second set of S's. However, if you read the article, you will see the word is correctly spelled in the first paragraph. (00:20:28)
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: The new sheriff ("Alice") told Rayburn that she has only been sheriff for a couple months and was still catching up on active cases. Rayburn replied, "Yeah, my daughter's case is far from active." The sheriff then told Rayburn, "My training is very different from the officers around here" - meaning college-educated (Ivy League?), more professional, more effective, and modern. Despite this, some of the sheriff's actions (e.g, walking unannounced into suspects' houses and/or without a proper warrant; questionable "probable cause"; shooting Rayburn to protect her brother) fell far short of the ideal. Perhaps most significantly, the sheriff gave Rayburn a warning shot and told him not to kill Dr. Boone... then she stood back and merely watched Rayburn push Dr. Boone into the pitfall and close the doors while knowing the doctor was severely injured and dying. These things do not show her purported superior training. (00:21:43 - 01:25:34)
Character mistake: Bart is sitting on a bench outside the hotel. After Detective Espada talks to the Mercer hotel manager/owner, he goes to talk to Bart. Bart has blood on both hands and lower left sleeve. Detective Espada is supposed to be investigating a fresh murder case that puts Bart at the scene, but he does not confiscate Bart's bloody clothes, conduct a gun powder test on Bart's hands to check for residue, or take him to the police station for formal questioning. Espada did not follow police protocol. (00:17:36)