Past Simple or Past Continuous?

1. Peter was staying at a seaside hotel on holiday when he met his friend. 2. While I was having lunch, the sun came out again. 3. Who were you talking to on the telephone when I came? 4. When Mary was reading the letter, she noticed many spelling mistakes. 5. She was going to bed when suddenly she saw a mouse. 6. We were sitting down to dinner when the doorbell rang.