Can someone check if my writing is correct?

I'd say it this way: I work in rescuing people's lives. During my first day of work, I saw my grandfather fall into the sea. He couldn’t get out because he was drunk. At that moment, I rescued him from drowning. It was a precious and valuable experience for me.

> I work in rescue people’s lives. This is a bit of a strange sentence. Is your job actually rescuing people’s lives? Are you a paramedic, or something similar? A life guard? > When my first time to work, I saw grandfather fallen into the sea. I would say something like: “The first time I saved a person’s life was when my grandfather fell into the sea.” Is it your grandfather or a grandfather? We can’t say “when my first time to work.” > At that time, I rescued him to swimming. Rescued him to swimming does not make sense. Consider something along the lines of, “I swam out to rescue him.” > It was my precious and valuable experience. It was *a* precious and valuable experience.

Use grammarly