部隊

1. Origins, structure, and basic meaning

• Structure: 部隊(ぶたい) is a group organized for military activity or a particular mission.
• Basic usage: It can refer to a military unit defending a bridge or to the rescue group in the example.

2. Common pitfalls and similar expressions

• The homophone 舞台
  • 舞台(ぶたい) is a performance stage or the setting of events. 部隊 is a group carrying out a mission, so the first example's rescue context refers to an organization.