Nothing distracts more than unrealistic events. To avoid such forced events, you need to do a little research or get creative. For example in the movie “Super 8,” there’s a scene where a man drives his pickup truck on to the train tracks to derail a military train. After his truck hits the train, the train and all its cars go flying off the tracks, allowing the monster inside one of the cars to escape. While visually exciting to see a train wreck, the scene loses some of its excitement by just noting that it’s impossible for a pickup to derail a train in such a spectacular fashion. Even worse is that after the truck hits the train, the kids find the smashed up truck and the driver still inside, seriously hurt. If a train really hit a pickup, it would not derail and it would tear a pickup truck apart, leaving no chance that the driver could survive.
It’s easy to overlook such trivial events, but how much more powerful would that scene have been if it had been more realistic? Comedies can get away with such twists of reality, but most movies cannot.
In “Prometheus,” the humans are examining the inside of a structure when two men freak out and want to get back to the ship. Inexplicably, these two men wind up getting left behind when the rest of the crew gets back to the ship. Huh?
How could two men, who left for the ship before the rest of the crew, not be able to get back to the ship before the rest of the crew did? Even more puzzling is that when these two men inevitably die, their death contributes nothing to the story. Some worm-like creatures get the men, they struggle and die, we watch them suffer, and we never learn why these creatures existed or why they attacked those two men. We also never learn how the deaths of these two men contribute to the story in any way other than to show two men die gory deaths.
Think of a screenplay like a Japanese haiku poem, which strives to say as much as possible with as few words as possible. You have no room in your screenplay for scenes that don’t affect the story or scenes that don’t make sense. You need a tight, focused story that draws the audience in and keeps them pinned to their seats. The moment you present an unrealistic scene, such as in a horror movie where a pretty girl inevitably decides to look for the serial killer in the dark by herself without telling anyone where she went, and the audience immediately realizes they’re watching a movie and loses the emotional impact of your story.
You don’t want to present anything that could sitract from your story or yank the audience away with unrealistic scenes. Keep it as real as possible. If you don’t know how police would really investigate a dead body, do some research to make your story accurate. It may take a little extra time to do so, but it will make your story more realistic and more appealing as a result. Plus you’ll get an insight into a new world that can create a sense of wonder that will appeal to your audience as well.