In Balance of Terror, after Kirk disabled the Romulan ship, he ceased firing and offered to beam the Romulan survivors aboard the Enterprise.
In Journey To Babel, after he disabled the Orion ship, he ceased fire and was going to offer the Orions the chance to surrender.
In Elaan of Troyius, after he partially disabled the Klingon ship, he ceased fire and allowed it to withdraw.
In each of these examples, Kirk was willing to destroy the ships and kill their crews while in combat, but once the ships were rendered disabled, combat was over.
Kirk could have easily killed the Gorn on it's back, killed Khan unconscious on the floor in engineering, the same story with the wounded Horta. James Kirk possesses mercy.
Charles Phipps wrote:
For TNG, I'll nominate "Hugh."
I wouldn't. Picard actions in not destroying the Borg (assuming it would have worked) are immoral and indefensible. Subsequent to that episode, the Borg went on the kill, enslave/assimilate and terrorize millions and billions across the galaxy. A vast area in the delta quadrant would have been freed of them. The invasive program would have taken down the Borg collective network, and while no doubt many Borg would have died, others of the many billions of Borg would have found themselves freed.
As Starfleet would later inform him, Picard's actions were wrong.
Least representative [of Starfleet morality]
Star Trek TNG: Pen Pals
What I've always found interesting about this episode (in terms of the prime directive) is the scene in Picard's quarters where we find that of the top six officers aboard the Enterprise, none of them agree as to what the prime directive means, how it should be applied, and two of the officers don't believe it should apply to primitive cultures in need a all. At least not the primitive culture in the episode.
In the end, Picard briefly transforms into James Kirk, he helps the primitives in such a way that they don't realize that a technologically advanced culture had helped them. Despite what the PD says, Picard doesn't just stand to the side and watch them die.
Unless they were willing to fire Russ and Phillips, there had to be a solution which ended Tuvix's life.
Tuvix was nothing more than a merging of Tuvok and Neelix, and not a original life-form. When the composite being was separated back into it's two original forms, the composite's memories apparently lived on in both Tuvok and Neelix. There was no surprise on their faces when they materialized in sickbay, they remembered the activities of Tuvix, just as Tuvix temporarily retained both of their memories.
There was no "death" of Tuvix.