Can we use past continuous for a finished action?

Question

There was a huge, shiny spaceship just above our heads. It did not move . It was pulling us off the ground. Seconds later we were inside it.

http://www.english-grammar.at/online_exercises/tenses/kidnapped-by-a-ufo.htm

I understand why past continuous was used, it took some time to be pulled off the ground until they reached the ship, but as the action was completed would it be possible to use past simple.

Answer 1

"There was a huge, shiny spaceship just above our heads. It did not move. It was pulling us off the ground. Seconds later we were inside it." doesn't sound idiomatic to me. Was the action of pulling so difficult that it had to take time? In my opinion, it is a quick action that needs not be in the continuous tense. It is also a good idea to show that the ship wasn't moving throughout the whole time.

The way I would say it is:

• There was a huge, shiny spaceship just above our heads. It wasn't moving. It pulled us off the ground. Seconds later we were inside it.

That's the way I see it:

However, the test disagrees with me.