u/Daakiness

What happens if I activate Sivriss, Nightmare Speaker's ability while one of my opponents controls a Rest in Peace or similar effect?

The ability says "return that card from your graveyard to your hand." I know Sivriss can "see" the exiled cards thanks to rule 701.17c, but I'm unsure if that means I can put the cards into my hand from exile if my opponents choose not to pay 3 life.

701.17c. An effect that refers to a milled card can find that card in the zone it moved to from the library, as long as that zone is a public zone.