When can past indefinite tense be used instead of past continuous tense?

"I answered the phone in my apartment and heard the sloping drawl of one of my students , Travis. " Miss Diana , " he said , "Could you come on down the stairs a minute?"

It was early May on the Great Plains . The University of Nebraska had just let out for the summer, and there was an aroma of pasture and cow everywhere, even - when the wind was right - - at the center of the city. I didn't want to be in Nebraska. I was 26 years old , and I wanted to be writing novels , not grading papers on detasseling corn."

These sentences have been recited from the following link:

https://www.washingtonpost.com/archive/lifestyle/magazine/2004/07/11/the-goddess-of-flowers/f0ca69bf-fb03-47e2-bd6a-460073fbdf52/

1) In first sentence why has past indefinite tense been used? My opinion is- we should use past continuous tense in this case, i,e we could say- I was answering the phone.....". Please, tell what you think.

Thanks to everyone of this forum.