How we cite our quotes: (Line)
Quote #7
IO. What good does life do me? Why do I not straight away throw myself from this rugged rock, so that I can crash to the ground and be rid of all my troubles? It is better to die once and for all than to suffer terribly all the days of my life.
PROMETHEUS. You would certainly find it hard to endure my trials. For me, death is not in my destiny: that would have been a release from my sufferings. As it is, no end has been set for my toils, until Zeus falls from his autocratic rulership. (747-756)
Basically, Prometheus tells Io that she doesn't even know what suffering is, so it would be stupid of her to commit suicide. He argues that he is the one who truly must suffer, because he is condemned to immortality. She may be trapped in a cow's body—but he's trapped in his life. Forever.
Quote #8
IO. This time the meaning of your prophecy is not easy to guess.
PROMETHEUS. Then don't expect to learn about all your future troubles, either.
IO. Don't hold out a benefit to me and then rob me of it.
PROMETHEUS. I will present you with one or the other of two tales.
IO. What tales? Put them before me and give me the choice.
PROMETHEUS. I give it to you. Choose: I will tell you plainly either the troubles that remain for you, or the person who will release me. (773-787)
Doesn't Prometheus seem like a bit of a jerk here? Like maybe he's toying with Io a bit? Or going on a bit of a power trip? It looks like even a guy who's tied up to a rock can't resist using manipulation to make Io and the Chorus his captive audience.
Quote #9
PROMETHEUS. Follow the bank of this river until you come to the cataract where the Nile pours down from the Bybline Mountains its holy stream, good to drink from. It will lead you to the three-cornered land of Nilotis, where, Io, you are destined to found a settlement far from home for yourself and your children. If any of this is obscure and hard to understand, please ask again and you will learn it more clearly. I have ample leisure—more than I want. (810-818)
Prometheus's words at the end here suggest that he has deliberately told Io's future in an unclear way—which will make her have to ask again, to hear him repeat it in more detail. As bad as this sounds, it's hard to blame him. He probably doesn't get many visitors, chained to a rock in Scythia.