In "The Death of the Ball Turret Gunner" by Randall Jarrell, the first two lines of the poem are:
From my mother's sleep I fell into the State,
And I hunched in its belly till my wet fur froze.
These lines reflect the innocence of the speaker. The place he describes in these first two lines is [metaphorically] similar to his mother's womb where he was safe. The "wet fur froze" brings to mind the birth of an animal into frigid temperatures—his birth into a cold and dangerous world. As he is born, he finds himself high above the earth.
Six miles from earth, loosed from the dream of life...
Reality has set in. His birth is not a literal one, but figurative in the sense that he is being introduced ("born") into a deadly reality—that of war—snatched early from the innocence of a young life...a "dream of life," which cannot compare to this waking nightmare.
I woke to black flak and the nightmare fighters.
When he awakens, there is "antiaircraft fire" all around, and enemy fighter planes. The comparison of the first two lines (to the person he is by line three) is the difference from being at home worrying about going out with the guys or going on a date, to a place where he and others face the fear and agonizing reality of possible death. The transition the author is trying to impart is the swift delivery into a world of violence—though the gunner is still a young man, very much innocent to this kind of world.
When I died they washed me out of the turret with a hose.
By the last line, the speaker has only left the safety of home to be thrust into this deadly war. And in the space of five lines, like the blink of an eye in a soldier's life, the young man has become aware of war, and his life is quickly claimed by it.
The turret was a small "sphere" that was attached to the "belly" of an aircraft, and from this vantage point, a man of small stature would sit hunched within, with access to two "50 caliber machine guns." It was his job to shoot down as many enemy aircraft as possible. Because he could do so much damage, enemy aircraft would aim first at the gunner in the turret to take him out. There was nowhere to take cover in the turret; when the author speaks of hosing the turret out with a hose (a "steam" hose), it was the quickest and cleanest way to remove the remains of the gunners killed. (Literary scholars see this last line as a metaphor for abortion; and subsequently, a commentary on the wastefulness of war. It is easy to understand how the rate of PTSD was much higher in ball turret gunners than other soldiers, for his life expectancy was much shorter.)
The identity of the speaker in the first two lines is that of an innocent young man who has only just arrived on the front of war, compared to a child in his mother's womb. His birth into the violent world of war is quick, as is his death, both of which are described in the poem's last three lines, as he becomes a casualty of war.