Stephen: A good plan today is better than a perfect plan tomorrow.
Charles Morse: Today, I'm-a-gonna-kill the mutha fucka.
Charles Morse: Never feel sorry for a man who owns a plane.
Charles Morse: We're all put to the test... but it never comes in the form or at the point we would prefer, does it?
Charles Morse: What one man can do, another can do.
Reporter #1: Mr. Morse, what happened to your friends?
Reporter #2: How did they die?
Charles Morse: They died... saving my life.
Charles Morse: You saved me.
Robert Green: Get over it, Charles - I just need you to navigate.
Charles Morse: You saved my life.
Robert Green: Well, I couldn't kill you with Stephen around. I'd have to kill him too, and he's the only one that knows how I like my coffee.
Charles Morse: Come on, you saved my life.
Robert Green: Buy me something nice when we get home.
Charles Morse: How'd you like your coffee?
Robert Green: Huh. I like my coffee like I like my women.
Stephen: Bitter and murky.
Charles Morse: I once read an interesting bit. Most people who die in the woods die of shame.
Charles Morse: Why is the rabbit unafraid?
Styles: 'Cause he's smarter than the panther.
Chosen answer: Although Bob intended to kill Charles (to obtain his wife and wealth), they unexpectedly were struggling for survival in the wilderness. Working together increases their chances of rescue, and Bob cannot survive without Charles' help. He therefore saves him from the rapids. Plot-wise, this makes Charles think that his suspicions about Bob may be wrong. Also, Bob is not a born killer, and may be hesitant about actually committing murder, particularly someone he had admired and respected. Bob likely planned to kill Charles when rescue was imminent and then claim Charles died accidentally. Regarding the title, because the movie is not based on a book of that name, the filmmakers probably chose it for its marketing value because it sounded dramatic. This is a suspense/adventure movie, and "edge" can have multiple meanings, such as being "on the edge," as to whether or not Bob will carry out his plan. It can also refer to the razor-sharp edge of a weapon, an "edgy" emotional situation, and so on.
raywest ★