The Destruction of the Halkan Civilization

In the mirror universe, Kirk urges Spock to take command of the ISS Enterprise, spare the Halkans and find a way to make peace to prevent the Terran Empire from collapsing. He and his landing party are then transported back to the Federation "real" universe, while their "evil" counterparts return in the alternate reality. The evil Kirk, now in command again, is determined to take the dilithium crystals from the Halkans or to destroy them as an example of what happens to those who dare to resist the Terran Empire. The Halkans are not willing to hand over the crystals and Kirk orders a torpedo barrage on their planet, rejecting a diplomatic solution recommended by Spock. The pitiless attack completely wipes out the Halkan civilization but also destroys the dilithium crystals on the planet. Spock points out that the loss of the crystals would not have happened if the Captain had followed his advice. Facing an unexpected and firm criticism by his first officer, a visibly nervous Kirk leaves the bridge and reaches his quarters.