Translation of "Inadvertently" in Russian

I missed it inadvertently.

Я пропустил это ненамеренно.

And inadvertently become a part of the problem.

и невольно стала частью проблемы.

- He fell into a slumber inadvertently.
- He dozed off even though he didn't want to.

Он невольно задремал.

- He put salt into his cup of coffee by mistake.
- He inadvertently put salt into his cup of coffee.
- He's put salt into his cup of coffee by mistake.

- Он случайно посолил себе кофе.
- Он случайно насыпал соли себе в кофе.
- Он по ошибке насыпал соли себе в кофе.