Continuity mistake: In the beginning of the movie, students pour out from the school. Margaret and Johnny walk up to Janet and Billy by passing between two tall boys making them apart. In the next shot, the boys are walking side by side behind them. (00:09:50)
Factual error: A few days prior to Warrens' visit to the Hodgson's family, Janet watches the British comedy TV series "The Goodies" on TV. The episode that she was watching actually aired on December 22 of the year in the UK. Later, when Ed records the interview with Janet, it turns out that it's December the 21st. (00:28:20 - 00:31:25)
Visible crew/equipment: When Ed is playing the Elvis song there's an unexplained arm visible in the reflection of the glass in the corner of the room. The arm is visible for around 1 or 2 seconds before moving. (01:24:00 - 01:30:00)
Other mistake: In the train scene, when Ed plays the two tapes separately, the first tape says," Help...It...Let...Go, Help...It...Let...Go." The second tape is then played, saying," Me...Won't...Me...Won't...Me." When played together, it should say," Help me, It won't let me go, Help won't, it me let go." Instead, it somehow turns into," Help me, it won't let me go, help me, it won't let me go." There aren't enough words in the second recording to fill or sequence the entire sentence(s). (01:45:00 - 01:49:00)
Continuity mistake: Hatchet marks are already visible on the door when Vic Nottingham arrives to chop through it.
Continuity mistake: The red napkin in Ed Warren's hand disappears and reappears several times while he sits at the breakfast table.
Factual error: No council house in Enfield has a cellar like that.
Factual error: Fireplaces in the house are not those of a 1930's British house, they are the wrong size (more USA dimensions). You'll never see a British tiled fireplace quite like that.
Factual error: The school sign, supposedly in the 70s, is showing an 11 digit telephone number. The number should only have nine digits in the 1970s.
Revealing mistake: During the scene near the end, at the climax of the film, when Ed is holding onto Janet for dear life outside her bedroom window, as Lorraine rushes over and pulls them back into the house, 'Janet' is a dummy.
Factual error: All four Hodgson children go to Enfield Grammar School. Enfield Grammar School is a single sex boys' school, so the two girls could not go there. In addition, grammar schools in England are secondary schools. While the two girls (aged 11 and 14) are of secondary school age, their younger brothers are of primary school age.
Revealing mistake: When the girl is hanging from the ceiling her hair is following what gravity normally does. This gives away that the set is actually upside down and she is really on the floor. If she were stuck to the ceiling her hair would've been down on her face.
Continuity mistake: In the middle of the movie during a non ghost activity kitchen shot the Pyrex bowl on the top shelf moves slightly from one shot to the next. You can see the full frontal pattern in majority of the movie, however, it moves slightly, revealing where there is no pattern visible on the bowl.
Answer: Valak was portrayed as a particularly powerful demon. In horror films demons are often portrayed as overconfident, and in this case it was thinking that Lorraine Warren would not be powerful enough to be able to defeat it. In addition, Valak revealed their name while Lorraine was in a dreamlike trance state, so it may have believed that she might not remember or make the connection at any point and be able to use it to her advantage.
dewinela