What is foreshadowed through Isabella's behavior toward Heathcliff in Chapter 10?

Catherine visits Heathcliff at Wuthering Heights with Isabella as chaperone. Unfortunately for everyone, Isabella has developed a crush on the dark stranger, but Heathcliff does not care for Isabella at all. The next day, Edgar is away and Heathcliff visits and finds Catherine and Isabella alone. It is foreshadowed that Heathcliff will use Isabella's attraction to him as a means of revenge.