Continuity mistake: Episode 4.18, "The Wall" - The dried blood on Claire's neck from when she was shot toward the end of the previous episode keeps disappearing and reappearing throughout the scenes at the Carnival. (00:35:00)
Continuity mistake: At the beginning of the episode, when Tracy is talking to the waitress and freezes her mug, the position of the mug changes in her hand between consecutive shots.
Chosen answer: Hiro's powers are still quite unreliable, and a locked closet door isn't a huge obstacle. Since Hiro knows he needs to rescue Ando, it's probably safer to try and bash the door down than risk teleporting to the wrong place or time.