How does Joe Haldeman use imagery in The Forever War?

Imagery:

"All you have to do is lean up against a boulder of frozen gas; there's lots of it around. The gas will sublime off faster than it can escape from the fins; in escaping, it will push against the surrounding 'ice' and fracture it...and in about one-hundredth of a second, you have the equivalent of a hand grenade going off right below your neck. You'll never feel a thing."

"...she kept running, careless leaping strides, and at the high point of one leap there was a flash and a rumble, and something big hit her below the neck, and her headless body spun off end over end through space, trailing a red-black spiral of flash-frozen blood that settled gracefully to the ground, a path of crystal powder that nobody disturbed while we gathered rocks to cover the juiceless thing at the end of it."