Acceptance - S4-E4
Continuity mistake: The second time Hiro goes to the rooftop and tries to save Tadashi he has ink on his face from stopping the photocopier from working. However when we cut back to him from Tadashi the ink has vanished, then when we do get the next shot of him the ink is back on his face again.
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 ★