Epidsode 19, Out of Sight. The part when Pru is alone in the house making the potion to vanquish the Grimlocks. She has already poured one potion, and is about to pour the second one, but then the phone rings, it's Phoebe telling her that Piper is hurt and that she can't get to her. When Prue hangs up the phone she walks back to the stove and grabs 2 jars of the potion. She never poured the second one.