無事

1. Origins, structure, and basic meaning

• Structure: 無事 (ぶじ) describes safety or freedom from damage. 無事に is adverbial; 無事で connects a state.
• Basic usage: A climbing party is reported to have 無事に戻った; an important package remains 無事で, bringing relief.

2. Common pitfalls and similar expressions

• Safety of a return and preserved condition of an object
  • The first modifies 戻った; the second predicates the package's state before linking relief. They are not ordinary case particles on a noun.