Revelations - S4-E22
Revealing mistake: When the group is fleeing from the cops, there's a shot of the road as they're turning. The camera used has a crack, or piece of debris, on it at the top to the left. The black line doesn't move as the camera pans across the road.
Chosen answer: Quinn's brother was going to be a recurring character, so "introduced" in this case referred to the actor becoming a semi-regular.
Jean G