Episode #4.8 - S4-E8
Continuity mistake: Humphrey knocks over the flower pot. Florence reacts in one shot from behind raising her arm, but the arm is down again in the instant reverse. (00:00:50)
Episode #4.8 - S4-E8
Continuity mistake: Everyone is in the cell examining the corpse. The prison guard nods when Dwayne says that they did a complete sweep of the courthouse; his arms are folded. Next shot, his arms are down his sides, and only a second later he folds them. (00:04:55)
Episode #4.8 - S4-E8
Continuity mistake: Goodman and Cassell are doing the whiteboard routine; when Humphrey asks about the 'refreshments', his marker is uncapped, while it has the lid in the shot before and after. (00:13:05)
Episode #4.8 - S4-E8
Continuity mistake: Inside Erol Dumas' kitchen, Florence holds the envelope with the money putting her fingers on the empty glove. During a quick cut on Humph though she suddenly wears the glove for the ending of the scene. (00:19:05)
Episode #4.8 - S4-E8
Continuity mistake: After the chat with the Commissioner, Humphrey gets infodumped on by his team. Dwayne passes him the insurance documents, then JP speaks about the personal effects of the deceased, just as Goodman split the papers given by Dwayne one per hand. Reverse shot and they are back one stacked on top of the other. Back to the previous angle, and they are divided again. And so on. (00:25:10)
Episode #4.8 - S4-E8
Continuity mistake: Dinner with the father, part 2. Humphrey is having trouble speaking, and his dad asks "Are you like this at work?" During that shot you can partially see that Mr. Martin Goodman QC is holding the glass of wine, while he's holding a fork in the previous and following. (00:29:25)
Episode #4.8 - S4-E8
Continuity mistake: When Humphrey is done with the murderer, he walks back to the stand, with Florence fawning over his performance. In the longshot Commissioner Selwyn Patterson 's arm is in the shadow, in the closer angle the shadow goes to half his pec too. (00:47:30)
Episode #4.8 - S4-E8
Plot hole: The way the murder happened (where was the gun shot from?) is entirely unknown for the first couple of days, not even a hint - it seems the investigators don't care at all about it, which is quite silly per se. More importantly though, knowing so little about the way the shooting happened would have at the very least prompted an analysis of the shirt to check the entry wound and any residual. During that sort of test the 'other substance' used in the trick would have been easily discovered (visually it is radically different up close and drying out), exposing the culprit.
Answer: Most likely they had only tropical exotic drinks, he wanted an old fashioned English beer.