What does fireinthehole mean?

"Fire in the hole" actually means "be careful", "stand back" or "something exciting/important is about to happen"

The origin of cave fire can be traced back to the history of underground coal mine (black coal mine), the most dangerous civilian occupation on earth. For most of American history, this kind of mining relied on the use of black powder or explosives to make rocks collapse.

Later, some American troops still habitually used "fire in the hole" as a warning language.

After all, this is a matter of personal habits, and we don't want to change it deliberately, so we can still hear two usages of "fire in a hole" and "fire" so far. But no matter how it evolves, the moment the slogan is shouted, it means that an area will be bombed, which may take several lives at once.

So we can't define whether the invention brings harm or benefit to mankind in one sentence. We just hope that the occasion where "fire" appears will never appear on the battlefield again.