Complex sentence: At the same time, Mrs. Potato Head sees Andy searching for the toys with one of her eyes that was left behind, which convinces the toys that Woody was telling the truth, but before they can leave, they are imprisoned by Lotso and his gang.
Split into simpler sentences: At the same time, Mrs. Potato Head discovers Andy is searching for them through her missing eye that she left behind, which convinces the toys that Woody was telling the truth. Before they can leave, they are imprisoned by Lotso and his gang.