2.4: At her dad's court in Milan, Silvia flirts with Valentine and mocks Thurio. When Proteus arrives, she greets him, engages in some witty banter, and then leaves.
4.2: Silvia is serenaded by Thurio and a band of musicians. She comes to her bedroom window after Thurio leaves and is hit on by Proteus, whom she rejects.
4.4: Silvia rejects the ring that "Sebastian" has been sent to deliver. She talks with "Sebastian" and asks about Julia.
5.1: Julia asks Eglamour to help her travel to the forest to find Valentine, who has been banished.
5.3: In the forest, Silvia is captured by a band of outlaws who say they're going to take her to their friendly leader (Valentine).
5.4 Sometime between the last scene and now, Proteus has "rescued" Silvia from the outlaws. Proteus nearly rapes Silvia but Valentine prevents the attack. (We don't hear another word out of Silvia after this.) The Duke shows up and says Valentine can marry his daughter so, Silvia is engaged without having uttered a single word.