Character mistake: When the EMTs are resuscitating Dr. Harris, they use a defibrillator despite their being on a wet metal dock. Not only is this highly dangerous to absolutely everyone present, it would be completely ineffective at restarting his heart as the water and the metal would dissipate the electric current too much for it to do any good. At the very least, they would have stabilized his spine then moved him to a dry surface before beginning defibrillation. (00:08:30 - 00:09:10)
Suggested correction: External defibrillators are self grounded and so can be safely used on wet or metal surfaces. https://danboater.org/travel-health-and-safety/are-aeds-safe-to-use-in-wet-environments.html.
AEDs are indeed safe to use in wet areas - but in the film, it is not an AED that is used. AEDs are automated, and not operated by humans, so as to reduce risk. Your link explicitly states the rescuer must not have direct contact with the body: they just apply the pads, then move back. In the film, it is shown in detail that the medic applies the paddles and then operates them while still in contact with the body. The mistake stands: it's a traditional defibrillator, thus incorrectly used.
Character mistake: In the Italian restaurant, Eddie is speaking jibberish, not Italian at all.
Suggested correction: He is speaking Italian.
I am Italian. He is speaking gibberish.
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: Near the end of the movie, Dr. Bennett told Nathan that he could live with her and be able to finish the school year (without having to transfer). Assuming Nathan was a minor (under 18 years of age), Dr. Bennett did not have the legal authority to simply take custody of Nathan. There are proper court procedures to follow; a judge would have to agree and sign a court order declaring Dr. Bennett as Nathan's (temporary or permanent) legal guardian.