Slave Island - S1-E7
Plot hole: After Storm's attempt to escape the Genoshan prison is thwarted, she ends up in the ocean right at the shoreline of the beach, where she is captured by a Sentinel. Aside from the fact that it makes no sense for a Sentinel to be hiding in the ocean in the event that a mutant tries to escape the prison, there is absolutely no way that a two-story tall robot could hide in the ocean right by the beach, as the water would be way too shallow. You can even see that the water level only goes up to the Sentinel's ankle area when it is standing upright in the ocean. (00:03:15)
Suggested correction: Perception. (1) The Sentinel isn't as close as it appears. If it were close, then she would have been caught in its waves as it emerges. Also, she would be looking only at its chest circle. It's several yards away. (2) She washes ashore. She fell from the sky. She couldn't have fallen from that great height into shallow water without hitting bottom. (3) It's also a two-story tall robot. Its weight would sink it into the sand. So it could have very well been down that deep.
Plot hole: In the season one episode The Cure, when Pyro and Avalanche are in the bar on Muir Island waiting for Mystique to arrive, Avalanche says "This friend of yours better show up soon or I'm going back to jail, just for something to do!" Rogue then comes in and Pyro suggests to Avalanche that Rogue could be Mystique, to which Avalanche responds "What do you mean it could be? Don't you know what she looks like?", leading Pyro to tell Avalanche that Mystique is a shape-shifter. This dialogue implies that Avalanche has no idea who Mystique is, which is further substantiated when Pyro and Avalanche kidnap Mystique later in the episode while she is in the guise of Dr. Adler, and Avalanche didn't recognize Mystique when she revealed her true form. However in this episode it is shown that Pyro and Avalanche were both previously members of Mystique's Brotherhood of Mutants, so Avalanche should already know who Mystique is without Pyro having to tell him. Rogue was also a member of that group yet neither Pyro nor Avalanche recognize her.
Plot hole: After Magneto and Xavier discover that their powers have vanished, Mr. Sinister is shown to be watching them through surveillance footage, zeroed in on their faces from a straight angle. At this point, Magneto and Xavier are standing at the edge of a cliff in the Savage Land, which is a jungle hidden in Antarctica. There's no conceivable way Mr. Sinister could have security footage of them from where they are located. Any camera would have to be mounted onto a tree, and the cliff is at a considerably higher elevation than the jungle itself, as well as a considerable distance away. Even if Mr. Sinister was able to zoom in on them from such a distance, the treeline being lower than the cliff would only allow him to view them from a low angle, and that's only if the cliff wall didn't obscure them. (00:20:00)
Plot hole: After Wolverine tells Gambit that he only knows how to pick pockets and steal candy from babies, Gambit attempts to retaliate by kinetically charging one of the bricks Wolverine is working with in order for it to blow up in his face. Anything Gambit kinetically charges makes a high-pitched humming sound, and Wolverine possesses a superhuman sense of hearing, so he should not have been caught unaware by it. (00:06:55)
Slave Island - S1-E7
Plot hole: When the Leader says "Take me to my car at once!", one of his guards goes to open the door to the room only to have Cable shoot the door with his plasma rifle. The Leader then says "The other way you fool!" and everyone in the room starts running for the windows that Cable shot out a few minutes earlier, which happened to be the only other way out of the room. As evidenced earlier from when Cable shot the windows out, that particular floor appears to be 8 stories up, so if everyone in the room exited through the windows, they would have all fallen to their deaths as all of them were regular humans with no superpowers. (00:17:40)
Plot hole: Towards the end of this episode, Jean Grey nearly falls to her death when a concussion blast from Cable's gun knocks her off a cliff, only for her to be saved at the last moment by Rogue. Apparently Jean Grey and the writers for the episode forgot that her telekinetic powers give her limited flight ability as well as the ability to slow falls, both of which she has demonstrated in other episodes.
No Mutant Is an Island - S5-E4
Plot hole: When Killgrave's bodyguard dumps Cyclops face down in the pool and leaves him for dead, it is night time. When Sarah is shown to have successfully resuscitated Cyclops, it is broad daylight. If Cyclops had been floating face down in the pool for several hours then he would surely be dead. No amount of CPR would have brought him back. (00:15:45)
Plot hole: This episode showed that Beast was an original member of the X-Men and also depicted the original X-Men battling Magneto. However, when Magneto attempted to break Beast out of jail in the season 1 episode "Enter Magneto", Beast said to him "I don't believe we've met. Magneto I presume."
Secrets, Not Long Buried - S4-E15
Plot hole: At the speed Cyclops is traveling in his mini-jet when he passes Watchdog's tower, he would have been long out of range before Watchdog could force him out of the air into a crash landing, considering that Watchdog had to take time to alert Solarr of Cyclops' presence and be ordered to knock him out of the air. (00:02:30)
Beyond Good and Evil: Part 1 - S4-E8
Plot hole: Beast comments on Mr. Sinister's new-found time travel abilities. However, Beast has no way of knowing that Mr. Sinister is time traveling. He only knows that Mr. Sinister is using portals, which could just as well be for teleportation. (00:18:40)
Beyond Good and Evil: Part 1 - S4-E8
Plot hole: Gambit remarks that Shard is his kind of time traveler. However, Shard was inside the mansion and Gambit was outside when he said that, and he had never previously met her, so there was no way he could have known who she was without having even seen her or even that she was a time traveler. (00:17:20)
Plot hole: Some of the footage Magneto is showing the delegates at the U.N. meeting includes footage Magneto could not possibly have had access to even if such footage existed, such as the X-Men having mission briefings in the War Room, the Morlocks living in the sewers or Warren Worthington emerging from being buried under several feet of snow at his secluded home in the mountains. (00:03:10 - 00:04:05)
Plot hole: Nightcrawler spends a good amount of time trying to escape the angry mob on foot when he could simply teleport away from them. (00:02:00 - 00:02:40)
Plot hole: Magneto states that he went to Washington, DC to witness Senator Kelly's assassination. But Magneto had no way of knowing about the assassination plot. Mystique was the one who was attempting to assassinate Kelly, and Apocalypse was the one who carried out the order. At this point in the show, Magneto had not worked with either Mystique or Apocalypse, and it's highly doubtful that Mystique would leak the plot, since it was supposed to be covert.
