When the Enterprise is fired upon by the planet-based disruptors, Scotty states that the Enterprise cannot return phaser fire because the "screens are at full strength." At no point in this or any other Star Trek series can phasers not be fired through shields.
it's not clear what happens to Fox's aide. He seems to get hit by a disruptor blast from an Eminian guard but he stood almost directly behind Spock who clearly wasn't injured in the engagement. He even holds the shoulder that was the most obscured by Spock when he falls.
After the landing party returns to its cell, Kirk asks Spock about their raid. Spock replies that they captured four disruptors. However they only had five in total (one for each party member), as one was taken from the guard knocked out in the cell and another from a guard near the disintergration booth, leaving only three to be captured later in this raid.
When approaching Eminiar VII, Kirk orders a yellow alert and shields up, yet in the next scene when preparing to beam down, when Kirk asks about ship's defenses, Spock mentions the screens are down. The time in which this whole conversation takes place before the transport is more than enough to attack the Enterprise, when it would've been safer to lower the shields once they began transport, and raised again, as shown in other dangerous situations.
Isn't Kirk's interference with Eminiar's war a serious violation of the prime directive on non-interference?
When Spock destroys the disintegration chamber, the door is open. Then the camera cuts immediately to a side view and the door is instantly shut.
So how did Fox get down to the planet? Anan says to destroy the Enterprise as soon as it drops its shields, and Fox can't beam down unless they drop the shields. Yet somehow he and his assistant beam down anyway.
When the first wave of casualties is declared, Mea 3 is labeled "dead" after a simulated teleported fusion bomb. But Kirk is standing right next to her and he isn't declared dead.
How do the Eminiarians fire a weapon based on sound ("Decibels - 18 to the 12th power") up into the vacuum of space at the Enterprise?
Spock: (referring to Mea 3) Yeoman Tamara, you are to guard this woman and keep her from immolating herself. Knock her down and sit on her if you have to.
Yeoman Tamara: Aye aye, sir.
Kirk: Actual war is a very messy business. Very, very messy business. I had a feeling that the Eminians would do anything to avoid it, even talk peace.
Fox: Diplomacy should be a job left to diplomats.
Kirk: Death. Destruction. Disease. Horror. That's what war is all about. That's what makes it a thing to be avoided.
Kirk: Sometimes a feeling, Mr. Spock, is all we humans have to go on.
Spock: Captain... you almost make me believe in luck.
Kirk: Why, Mr. Spock, you almost make me believe in miracles.
Kirk: All right. It's instinctive. The instinct can be fought. We're human beings with the blood of a million savage years on our hands, but we can stop it. We can admit that we're killers, but we not going to kill today. That's all it takes - knowing that we won't kill today.
Anan 7: What kind of monster are you?
Kirk: I'm a barbarian. You said it yourself.
Anan 7: I had hoped I'd spoken only figuratively.
Kirk: Oh, no. You were quite accurate. I plan to prove it to you.
McCoy: Well, Scotty, now you've done it!
Scotty: Aye. The haggis is in the fire for sure.
Scotty: The best diplomat I know is a fully activated phaser bank!
Spock: Sir, there is a multi-legged creature crawling on your shoulder.
The United Federation of Planets is mentioned for the first time in this episode.