The Phalanx Covenant: Part 2 - S5-E2
Continuity mistake: When Xavier and the others are approaching Cyclops, Storm, Rogue and Wolverine, Magneto is shown wearing his helmet and Gambit is shown wearing his trenchcoat. When it changes to an overhead shot of the group, Magneto is no longer wearing his helmet and Gambit is no longer wearing his trenchcoat and his normally-black headgear is colored blue. (00:19:20)