Audio problem: Right at the end after Heather reveals that Ellen taped over the birthing tape with an episode of thirtysomething, someone says "which one" but no one in the crowd moves their lips.
Visible crew/equipment: When Spence breaks the bookcase, stage lights can be seen over Ellen's head.
Continuity mistake: There is a large black cue ball on a wooden base beside the staircase at the bookstore When the crowd rushes past it it gets knocked to the floor and bounces away, but immediately after in the next shot it is back on the base, then it is gone again.
Answer: This groundbreaking episode was in the fourth season, episodes 22 and 23.
Jason Feng