Walking away is a realistic thing, but generally, waiting for a moment and thinking is probably more realistic than moving forwards only to turn back. In those kind of fight or flight scenarios, once you've made a pick, you've pretty much made. I'd include it. It's a very human, very guilty moment, and done properly, it would be very powerful.
Reminds me of this one book I read, a sci-fi book where the protagonist was a street-kid from a poor planet who ended up becoming a rock star. There's one scene where a desperate girl runs out of a house while he's walking past, grabs his arm, and begs him to save her from someone threatening to kill her. He shakes her off and hurries away. It bugged me when I first read it (I was 12 or something then) but thinking back on that story, I'd say that was the best scene. Because people really are like that. People decide not to get involved, out of fear or to avoid a bother, or they convince themselves the situation wasn't what it seemed to be, or get wrapped up in themselves and fail to notice suffering. If we were all the kind of heroes that are a dime a dozen in most stories, we wouldn't have the kind of problems that we have. But not being those kind of heroes doesn't make us bad guys, either.
If I'm asking for advice on a story idea, don't tell me it can't be done.
The reason for this little detail is because I want to point out how Evil thrives on. Of course the average person wouldn't hesitate to do something about it if it's straightforward: to force the attacker away, or call the police if you're feeling so shy. We see it in movies and fiction all the time and most of the time we're taught who to root for. But in Real Life, when we're there.. it gets confusing.
You have a pit in your stomach that makes it difficult to think, and it becomes more a question of self-preservation; we don't want to get involved because of fear or indifference, or possibly because we think the victim does deserve it. As long as it doesn't happen to me, why should I be bothered? Similarly if you saw a bank being held up, would you try to stop the robber? You can ask ambiguous questions:
And I want to show the consequences of our indifference. You can turn away and pretend you've imagined it - easy enough. Then watch what happens when you disappear from the scene. But I think readers will skim over this background bystander anyways.
edited 18th Apr '11 2:43:29 PM by QQQQQ
Fuzzy Orange Doomsayer
Correct me if I'm wrong, but didn't Irreversible do this with the rape scene?
That's Feo . . . He's a disgusting, mysoginistic, paedophilic asshat who moonlights as a shitty writer—Something Awful
Ah, yes. While I felt ill through the entirety of that scene — the part which unnerved me so much was that the guy in the background comes along, takes a step closer; he watches for a second and then walks away. Nobody else came. He could have helped avert the tragedy. (Dude should've been Harry Callaghan. 
"You feel lucky now? Do ya, punk?")
edited 18th Apr '11 7:35:28 PM by QQQQQ
Imagine a scene where it is night. A man walks down into an underpass, and in the lonely tunnel he encounters someone who makes him ill to the stomach. Because this someone knows the man. He hates the man's guts to the fiber. So this someone beats the man down hard to the ground out of pure, cold rage, knocking the wind out of the man.
Before this someone starts a No-Holds-Barred Beatdown — someone else comes across the scene in the distance. He glimpses what is going on, takes a step or two towards, and then just leaves.
I wonder if it makes a difference adding in this little detail of the bystander? Is it even a realistic reaction? What do you think? Or should the bystander at least try and help anyways?
edited 17th Apr '11 10:34:58 PM by QQQQQ