While we’re on the subject of stock phrases involving death…
My student was unaware that he had written a truly arresting statement, one that might be expressing a deep truth: We all die in a heartbeat, so to speak, or at least we all die with the cessation of heartbeats.
He didn’t notice that because it wasn’t what he meant. He was trying to emphasize the nobility of our military, that they would not hesitate to give their lives for the country. That’s what “in a heartbeat” means: instantly, without hesitation.
You’ve used the phrase, I’m sure. “I’d marry him in a heartbeat!” “I don’t know why you can’t make up your mind—I’d take a job like that in a heartbeat!” Note the enthusiasm as well as the promptitude conveyed by the image.
And I’m sure my student also intended to convey the enthusiasm, or at least ready willingness, of the soldiers.
In fact, in terms of its intention there’s nothing wrong with his sentence. But in terms of its expression, what he means as fervent praise becomes comical because the phrasing seems both self-defining and self-contradictory. The hapless reader—or at least the reader for whom words evoke pictures—is bounced out of the essay to contemplate the bizarre vision of soldiers dropping suddenly dead all over the place to protect their country in some unknown way.
That’s the problem with formulaic phrases and clichés: they jump onto the page whenever they see the chance, not bothering to pause in the writer’s mind to see if they are truly the best words for the job. And sometimes, as here, they are absolutely not.
If only my student had taken the time to see what he meant to say: to picture soldiers unhesitatingly obeying the order to advance into battle, conscious that they might be killed but fully willing to make that sacrifice. That phrasing evokes tears of admiration and pity. For pacifists it might evoke anger against the waste of war. But it would not, for anyone, evoke puzzlement or laughter.