We've all seen it. One lone hero, or a small group of heroes, must fight there way through some organization or area, and while they are fighting, they somehow manage to take down hundreds of people, sometimes even thousands, and the enemies, which may be a crime group or cops on the bad side of the law, never back down and continue throwing their men at this unstoppable force made via storyline. Nor do they stop and say we are running low on men, as happens all the time in real life.
A perfect example is the movie Safe. The lone hero is trying to help a little girl with important information. He must fight his way through both the Chinese and Russian mafia, as well as a bunch of corrupt policeman. Single handedly, this man mows his way through a thousand people, but there are still more, no stopping the tide.
This trope only applies to near life situations, not in video games, where the tactic of some bosses is to drown the hero in enemies. Neither does it applied to war situations, where there is an expectation of losing men.