Continuity mistake: Maya's necklace disappears between shots when she accuses Sylar of killing her brother.
Continuity mistake: Right before Sylar shoot Maya, you can see she already has a bullet wound on her chest.
Continuity mistake: Season 2, episode 11, "Powerless":. In Mohinder's kitchen, when Sylar cocks the hammer of the gun he is holding on Mohinder, he is holding the gun with his arm straight and the gun completely level. The angle changes just as Sylar says "Maya, I need you to stay calm", and now his arm is close to his body and bent so the gun is pointing at Mohinder at an upwards angle. There was no time for him to move his arm in between shots. (00:03:30)
Chosen answer: Because he's an idiot. From the story point of view, they needed the vault to actually be physically open so that the release of the virus would be a credible threat. Unfortunately, this required that Peter conveniently forget that he could simply walk through The Wall and use his telekinesis to tear the door open instead. Peter's increasingly large arsenal of abilities, where he ended up having pretty much any ability required for any situation, led to a situation where it became necessary to either have Peter apparently forget that he had a given power, as with the vault door scene, or become naively trusting, as with his refusal to scan Adam's mind to confirm his good intent. This problem, which simply made Peter look increasingly dumb as the show progressed, may well have been a key factor in the decision to severely reduce his ability during season three.
Tailkinker ★