Plot hole: The murder as described makes kinda sense (it's a device used in other works of fiction), but not at all as shown; the person hiding in the bathroom closes the door to the point of making it click, and opens it also with a click. Even panicked, the other person in the room is going to hear the sound of a lock right behind him. The door should have been closed only partially. Moreover, the bathroom door is right by the front door closed just by the door chain, and Philip Marston had the door unlocked and with just the chain to break; the bathroom door was fully in his view the whole time.
Other mistake: The text message used as ploy to cover up the murder was sent at 17:44, but during the flashback showing the killer setting up the murder scene, a wristwatch on the vanity is at about 10 o'clock. (00:44:25)
Continuity mistake: After the obligatory ultimatum visit by the Commissioner, Jack asks Florence for good news. When she chirps that she -really - found something, her hands drop in the close-up, but are holding the headphones steady and up in the next shot. (00:32:25)
Continuity mistake: When Jack speaks to Florence about his ambiguous intention to spend some quality time with the Commissioner, he changes position in between shots, with his excited fist raised while his left hand disappears from sight. (00:15:10)
Murder on the Day of the Dead - S7-E5
Other mistake: Something happened to Daisy Anderson, so everyone starts looking for her car. JP says it is locked, but in the close-up of Jack looking inside from the window, you can see the knob of the lock is pulled up. That car is unlocked. (00:06:50)
Character mistake: Florence grabs the victim's phone with a tissue to avoid leaving prints...but then uses her other bare hand to go through her messages via touchscreen. In many other scenes she's just seen wearing latex gloves. (00:12:30)
Murder on the Day of the Dead - S7-E5
Continuity mistake: At the beginning of the episode, Darlene asks, and Jack turns to point with his cane where Dwayne went. Next shot and seen from behind Jack never moved, he's facing ahead and left. (00:01:45)
Murder on the Day of the Dead - S7-E5
Factual error: The 1966 Ford Mustang 289 belonging to the victim has registration plates from Hawaii, but "DY 536 HR" does not follow the correct format for Hawaiian license plates at that year, or any year for that matter.
Murder on the Day of the Dead - S7-E5
Other mistake: The day of the murder was February 1st 2018, a Thursday, exactly as stated also by the answering machine early in the episode. When Jack checks out (really really late, while any investigator would have easily worked with that data right away, asking them to the provider even, together with the cell phone info) the victim's satnav, it says that her 1 PM trip happened "Sat", a Saturday. (00:04:50 - 00:34:55)
Murder on the Day of the Dead - S7-E5
Continuity mistake: When Jack and Florence talk to Hugh, Florence's top when she is shot from behind has the two straps on her left shoulder about one inch apart, while they are joined close in the front views. The mistake goes on throughout the whole scene. (00:32:50)
The Healer - S7-E4
Continuity mistake: When at the beginning of the episode Pastor Steadman King is holding brother Marius to heal him with faith, he's holding him by the arms, the wrists, the palms, in a continuous jump between cuts. (00:01:30)
The Healer - S7-E4
Continuity mistake: Florence is telling Jack about the identity of the victim. His hands keep changing position between shots on the Steadman King poster he is holding. (00:05:35)
Continuity mistake: In the first part of the denouement, DI Jack Mooney is waving the victim's book around holding it in one hand when shot from the front, both hands from the back. (00:42:25)
The Healer - S7-E4
Continuity mistake: When Jack is inspecting the cup finding a sharp and unpleasant scent, Florence's hand changes position on the writing pad (stops writing and lowers the pen, vertical pen, horizontal pen) between shots. (00:07:00)
Continuity mistake: During the toast, Gilly White staggers for a moment. As different camera angles alternate, she is holding the champagne glass either sticking a finger out or not. (00:01:45)
Continuity mistake: Dwayne's bushy cover has been blown, so he nonchalantly walks out and greets the stern-looking Audrey. He opens his arms when he says her name, but in the reverse shot he repeats the movement, as he was still pretending to scribble on his pad. (00:14:00)
Continuity mistake: After the chat with the hotel manager, Jack and Florence are in Stephen's room. The level of drink in Stephen Marston's cocktail glass changes between shots - it's half full when Jack is straining to sit down, and is back up right at the cut. (00:35:25)
Continuity mistake: DI Jack Mooney is looking at the coroner report on the PC screen. He changes his stance and is initially hunched over and then straight, but the person in the foreground is keeping the exact same posture every time the camera cuts to Dwayne. (00:25:35)
Plot hole: There is simply no way that the cheating presented in the episode, with the player reaching in his pocket to mark the cards, consistently for over 5 years (!), and wearing the same obvious prop, could go unnoticed, especially in official tournaments with millionaire prizes, on camera even.
Continuity mistake: Office scene with the poison being revealed. Dwayne in his snazzy detective suit interjects that you have to know the right, or wrong people to get a hold of it. In the wider shot (whole room in frame) Danny John-Jules' left hand covers the cuff of his blue shirt, while in the closer angle the shirt is perfectly visible. (00:13:50)
Answer: Most likely they had only tropical exotic drinks, he wanted an old fashioned English beer.