Character mistake: Throughout season 3, whenever someone visits Henry in prison, the word "VISITOR" on their visitor tags is misspelled as "VISTOR."
Unquiet Mind - S2-E1
Character mistake: When Walt is coming up to Mars cabin he hears a gun shot, he then re cocks his gun ejecting a live round, since he has not yet fired it. (00:20:30)
Answer: Something he made up.