To imprint a split card, you pay X equal to card's mana value, determined by the combined mana cost of its two halves. If the copied card is a split card, you choose which one side of it to cast, but you can't cast both sides.
Panoptic Mirror
The creation of the copy and then the casting of the copy are both optional.
As Panoptic Mirror's triggered ability resolves, it allows you to create a copy of one of the instant or sorcery cards imprinted on Panoptic Mirror in the Exile zone (that's where the imprinted card is) and then cast it without paying its mana cost.
Magic: The Gathering · ™ & © Wizards of the Coast · Illus. Glen Angus
Card data via Scryfall. Rarix is fan-made; not endorsed by the rights holders.
