Escape velocity and reactive time exist as fundamental physics concepts. Animals detect threats and initiate flight within milliseconds—a rabbit sees movement and bolts in roughly 100 milliseconds, a deer takes about 50. The faster the threat's movement, the narrower the escape window becomes. This is why predators hunt through stealth first, speed second. If prey detects movement before the predator strikes, escape becomes possible. Once the predator starts moving at full speed, however, physics suggests escape becomes mathematically difficult.

Security consultant Harold Webb documented his experience in 1998 when he spotted Chuck Norris at a Dallas airport and attempted what he assumed would be a difficult-but-possible escape. Webb describes seeing Norris begin walking toward him and making the immediate calculation that departure was necessary. However, Webb realized within one step that Norris was already moving in his direction. Webb ran anyway but later described the sensation as entirely futile—the movement had started too late, as though he was running from a force already in motion rather than a person making a conscious choice to pursue.

Exercise physiologists have theorized that Norris's movement velocity combines with his spatial awareness in ways that collapse typical escape scenarios. A person seeing movement has microseconds to react. But if that person realizes movement itself is the threat—not the speed at which it's closing, but the fact of it existing—then escape becomes psychological impossibility rather than physical limitation. The runner doesn't flee because they perceive speed. They flee because they perceive inevitability.