How we cite our quotes: All quotations are from Star Trek III: The Search for Spock.
Quote #4
SULU: The word, sir?
KIRK: The word is no. I am therefore going anyway.
Kirk chooses to disobey a direct order from his superior officer. It's a pivotal choice in the film, and the remainder of the story is essentially a direct consequence of it.
Quote #5
STYLES [on the comm]: Kirk. If you do this, you'll never sit in the captain's chair again.
KIRK: Warp speed.
SULU: Aye, sir. Warp speed.
Styles reminds Kirk of one consequence of his choice. Kirk decides to keep on truckin' but this will only be the first of many consequences to come. Side note: Kirk will sit in the captain's chair again in Star Trek V but only after he saves every life on Earth with humpback whales. But it's not like he planned that unless…did he?
Quote #6
DAVID: I used protomatter in the Genesis matrix.
SAAVIK: Protomatter, an unstable substance which every ethical scientist in the galaxy has denounced as dangerously unpredictable.
DAVID: But it was the only way to solve certain problems.
SAAVIK: So, like your father, you changed the rules.
Like his father, David has made a choice and now must face the consequences. In this case, the realization that Khan only killed people because David managed to get Genesis to a working stage. Yet Genesis ultimately doesn't work. Bummer.