Continuity mistake: The exit door and stairwell outside of the town hall are shown to be at the very edge of the building when Proteus goes through it. When Xavier, Beast, Rogue and Wolverine use the same door and stairwell, the building suddenly stretches on for several more feet. (00:13:20 - 00:13:55)
Continuity mistake: When Proteus leaves the town hall, the door he exits is shown to lead into an alleyway. Moments later when Moira exits through the same door, it is shown to be leading into a corridor in the same building. (00:13:15)
Continuity mistake: When Xavier is speaking to Proteus telepathically, the position of his shirt and jacket sleeves go from being a few inches below his wrist in one shot, and then just slightly under his wrist in the next. (00:12:55)
Other mistake: Moira's arms are disproportionately long when she rescues Xavier from falling into the pit. (00:12:30)
Audio problem: The amount of crowd noise during Joe McTaggert's speech is inconsistent with how many people are shown in attendance. The noise would suggest at least a couple hundred people, but shots of the crowd only show a few dozen. (00:08:25 - 00:10:20)
Audio problem: When Joe McTaggert is saying "If the boy shows up, keep him out of sight until after the vote. If you don't, all of our work will be for nothing," he has suddenly lost his Scottish accent. (00:07:40)
Revealing mistake: When Proteus is leaving his father's home while possessing the police officer, the green glow of his eyes doesn't stay in place as he is moving. You can see the green glows leave his face and float in midair with the eye slots on the face turning black. It appears that the animators couldn't keep the glowing eyes synchronized with the body movement. (00:07:30)
Continuity mistake: When Moira is saying to Proteus "Kevin it's time to come home," you can see that Rogue is suddenly not wearing any lipstick. (00:04:05)
Other mistake: When the two civilians are walking past Joe McTaggert's campaign posters, they are shown to be walking unusually fast, almost as if the ground beneath them is moving them forward between strides (similar to as if you were walking on a moving sidewalk inside an airport). (00:03:00)
Continuity mistake: At the very end of the previous episode after Proteus had messed with Wolverine's sense of reality, Wolverine is shown whimpering in an open area. When Wolverine is shown at the beginning of this episode still whimpering, he has suddenly moved next to a treeline. Given the state of shock he was in, it's doubtful he would have gotten up and moved. (00:02:00)
Answer: Chris Potter, the original Gambit voice actor, did indeed quit the role in the 4th season. His last episode was The Phalanx Covenant Part 1 so it seems reasonable that Fox would limit the use of the character even though it was recast. It doesn't appear that Potter left the role due to animosity, he stated in an interview that he wished to play Gambit in the first live action X-Men film.
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