*Spoiler Ending Warning*
There is a big flaw in the murder set-up. It is initially believed that Marco Bergman jumped to his death as a suicide having read the scathing review of his latest collection. Yet he was blind, as we only find out towards the end. So why did his daughter leave the newspaper to suggest he'd been reading it, as her brother, who was not involved with the set-up, would realise he couldn't have possibly read it. Even if she did it to throw suspicion off herself, he would have found it odd. This also makes it unbelievable that the brother turns up later accusing Donna Henry of having caused Bergman's death, waving the review he knew his father couldn't possibly have seen anyway!
Louise takes one syringe of insulin from Carrie which both makes Carrie panic and run out to the balcony, from which she appears to be about to jump, and Jonathan suggest this could make her lapse into a diabetic coma (which it very possibly could). Yet anyone relying on regular injections of insulin would always carry a complete supply with them for precisely this reason, especially given she was away from home and was shown earlier taking a syringe out of a large first aid kit from her bag, which she still has with her. Carrie's reaction is way over the top, especially as she has her 'phone with her, while her brother is in the house and would have heard her screams.
This is supposed to be a slightly 'softer' crime – no locked doors or dead bodies – and the culprit actually asks "Did I commit a crime? Well, I suppose it wasn't a very nice thing to do." Erm… No, it wasn't very nice and yes, you did commit several crimes: conspiracy, kidnapping, assault… It seems unlikely that the girlfriend, even with a warning, wouldn't have gone to the police given what she went through, especially since it happened right outside Houseman's gate! Yet nobody is actually charged with anything!
During the very first scene - the reenactment by Eyes and Ears of the discovery of the first body - when the cars stop it is revealed that the victim was tied to the back of the nurse's car on rather a long rope. Yet during the car chase that precedes the discovery, despite some good camera angles, there are two places (as the nurse turns her car violently left and then as the car hits the grass verge and comes to a halt) where you can clearly see there is nothing attached to the back of the car at all.
When Heather is getting ready in the locker room and talking to Parnevik, she puts on her jumper and her shirt collar is underneath. Yet in the reverses, her collar is outside the jumper. This goes on for the entire scene, with the collar moving from inside to outside depending on the camera angle.
During the scene near the beginning, where Adam and Velda are having a meal and Jonathan has interrupted them, Velda is seen to top up her champagne glass, then continue to devour her meal. In the conversation that follows, she takes a couple of big gulps of champagne and her glass is clearly seen to be half full. Then a second later during the same conversation, the glass is suddenly completely full again, and moments later it is almost completely empty, with just a drop of bubbly remaining and a great big lipstick stain on it that wasn't there previously.
Two things don't make sense in the gymnasium scene. Heather is warned to get back against the wall to avoid the killer getting behind her. Yet her body is discovered in the middle of the gym. Also, the inspector calls for a key, which someone has to go and fetch. Why, since they are armed officers, wouldn't one of them at least just shoot out the lock, given their colleague is apparently being strangled?
Heather Davey's killer has gone to supposedly great lengths to set her murder up so that it will be thought of as part of the series of 'Daisy Chain' murders. The jacket has been rigged, he can be first on the scene. Why on earth, then, would he arrange for the 'murder' to take place inside a locked gymnasium? Why not set off the booby trap in the hallway? She's on her own. Nobody would have seen what actually happened, and it would have been a lot more likely that the murderer might have escaped unnoticed. Instead, he arranges it in a locked room, with an impossible escape for the supposed killer that just draws attention to the whole thing. Poetic licence maybe, but it makes no real sense. Two other things that are very dubious: this is a large gymnasium in a modern college. Fire regulations would surely have made it impossible to build this without at least one other exit (having another exit would again have given the killer a possible escape and made setting it in the gym feasible). The second is that is the killer himself who draws attention to the flecks of blood on the jacket she'd been wearing and tells them it wasn't hers! He's talking to a reporter and a magician's aide - he wouldn't have to repeat it, and he'd be far less likely to be caught!
Jonathan mentions they are having trouble with getting a surrealist painting for the show. Having had the Magritte rejected, he gives two other choices, one by Salvador Dali or The Scream by Edvard Munch. If they were looking for a surrealist painting, they would not have chosen Munch, since he was an Impressionist painter, not a Surrealist.
The WPC is supposed to have been killed by the serial killer, who strangles their victims. However, any suspicious or violent death is required to be reported to the coroner, who would carry out a post mortem examination and would have easily discovered that the little red mark on her neck was not a sign of strangulation – and presumably that her ribs had in some way been crushed or bruised by the pressure of the jacket. The plot relies on this being one of a series of murders, but it would have been obviously singled out.