Final answer:
After a traumatic event, Brian's senses become extremely heightened, allowing him to see the minutest details in his environment and hear the slightest sounds, aiding his survival.
Step-by-step explanation:
Brian, the protagonist, experiences a heightened awareness of his senses following an intense and traumatic event. His perception is so intensely improved that it becomes almost superhuman in nature.
He now sees the individual leaves, their veins, and even the insects upon them with unprecedented clarity, and hears the ripple of each water droplet as a distinct sound.
He notices the prismatic colors on dewdrops and discerns the faint music made by gnats and dragonflies. Brian's previously normal senses have been amplified to such an extent that he hears the inaudible like the humming of insects and perceives minute details like the ripple effects of a fish swimming or the shades of color in a soldier's eyes.
This extraordinary sensory enhancement helps him in his desperate situation, as he can see dangers more clearly, like noticing the soldiers with their guns and anticipating their actions.
His acute sense of hearing lets him detect the reports of the rifles being shot in his direction, allowing him a better chance at evading the threats. Such sensory sharpening under duress signifies both the body's response to extreme stress and the potential for human senses to perceive beyond their usual capabilities.