Continuity mistake: When Kris is looking at the photo album just after Dean's funeral, she turns a page and there are no photos on either page as you can see. When the camera changes, two photos have appeared on the one page. (00:13:45)
Factual error: Quentin steals Adrenaline from an ER crash cart. That would be believable except, I am a nurse, my husband is a paramedic, my father in law is a doctor. Under NO circumstance is a crash cart to be left unattended, they are locked up when not in use. Also, Adrenaline would NOT be in a cart like that, that medicine is locked up. ER crash carts, like what was used in the movie, would only have had a defibrillator, gel for the defibrillator pads, gauze, dressing and first aid supplies, nothing more.
Continuity mistake: When Nancy and Quentin are talking in the hallway, Quentin's hands are constantly moving instantly. (00:17:30)
Chosen answer: They were upset because they realise that Freddy is coming to get revenge on them for his death.