please give the below poem's summary

There Have Come Soft Rains

BY JOHN PHILIP JOHNSON

In kindergarten during the Cold War,

mid-day late bells jolted us,

sending us single file into the hallway,

where we sat, pressing our heads

between our knees, waiting.

During one of the bomb drills,

Annette was standing.

My mother said I would talk on and on

about her, about how pretty she was.

I still remember her that day,

curly hair and pretty dress,

looking perturbed the way

little children do.

Why Annette? There’s nothing

to be upset about—

The bombs won’t get us,

I’ve seen what’s to come—

it is the days, the steady

pounding of days, like gentle rain,

that will be our undoing.

Explanation: At the beggining, when the character describes his kindergarten school hallway, he shows how the children were lead when there was an atomic bomb drill alert, specially when he mentions the position in which they had to stay ("[...] pressing our heads/between our knees, waiting.") Then, he describes a classmate, Annette, that was probably killed during one of the drills when he says "Why Annette? There's nothing/to be upset about - ", and reflects on what is going to happen because of the war. He realizes that the most dangerous things aren't the bombs, but the war itself, if it keeps going on and on, as he shows in "it is the days, the steady/pounding of days, like gentle rain,/ that will be our undoing."