The electrocution shown at the beginning was impossible as depicted as the person electrocuted was shown wearing thick rubber soled shoes and they were not touching anything to complete the path for electricity. The shoes would also insulate the person from the electricity.
When Hana is walking to her car in the parking lot before being confronted by Michelle, she uses the remote to unlock it and the siren is heard chirping. Then the car turns over but will not start. When she gets out and opens the hood you clearly see the battery is disconnected. Neither the remote nor the starter would operate in that case.
When police go to arrest a suspect, all exit points are covered. In the event a suspect rode away on a bicycle, the officers would use their car to pursue, not on foot.
When Sophia finds her parents after her confrontation with Michelle, she takes the tape off her mother's mouth, but not her father's. However, the tape on his mouth is gone a few moments later.
After the study session, Michelle confronts Sophia about their planned meal and Sophia says it is only 8. The sun angles show it is not that late in the day, it was filmed closer to midday.
Michelle fires 14 rounds from the officer's handgun and then it clicks. The slide was not locked back, which is what happens with a semi automatic handgun after the last round fires. Coupled with the lack of recoil shown, it was obviously a prop gun with sound effects added later.
When Michelle confronts Sophia by standing in front of her car, Sophia starts blowing the horn so she can move the car and yelling for Michelle to get out of the way. The car was pulled in to a parking space, and there was plenty of room behind it so Sophia could have gone in reverse. Michelle standing at the front of the car would not have prevented Sophia from backing it out of the parking space.
Michelle sees Hana and a male student get into Hana's vehicle and the engine is heard starting as if they are going someplace. Michelle is pushing her bicycle. Later Michelle blackmails Hana with a photo showing her wearing the same outfit as earlier straddling the male student in her vehicle with the door open. Michelle on a bicycle would not have been able to keep up with the vehicle, and as such would not have been able to take the picture.
The credited cast names do not align with the last names spoken in the movie. Jamie Luner's character name in the credits is Ashley Allen. When Michelle first speaks to her, she calls her Mrs. Daverston. Josh Blacker's character in the credits is Detective Jenkins. After finding evidence at the break-in, Sophia calls him Detective Burke. Sarah Grey's character name in the credits is Sophia Allen, but when she is announced for the competition her name is given as Sophia Daverston.