When I died they washed me out of the turret with a hose.
Hold up y'all! We've been listening to a dead guy? And P.S.: gross!
Randall doesn't mince any words in the last line. Kind of like the title, it's just straightforward, stark reality—just the facts, ma'am, just the facts. And the facts are pretty grizzly.
The gunner's remains are cleaned out of the turret with a steam hose.
Let's take another look at this line (as unpleasant as that may be) and think about the poem's birth imagery and the metaphorical aspects of the turret.
Remember the way the gunner "hunched" in the turret like a fetus in the womb? Well, if we carry that reading through to this last line, we have the gunner being reborn from the turret/womb. But instead of being born into life as a child from a mother, the gunner is born into death from the womb of "the State."
Essentially, in this line of thought, it's as though nations breed death.
A figurative reading of the poem's final line also suggests an abortion—the washing out of the fetus from the womb. Like an aborted fetus, the gunner's life (and the lives of all young men and woman lost to the war machine of nations) doesn't reach a full, completed state.
And unlike the dignfied, heroic deaths we are often told about when it comes to war, this poor gunner is disposed in the same way one might clean a car or a garbage can. There's nothing noble or heroic about it.