Question

she mentioned the police and shouted at him. (change simple sentence)

Answer 1

She mentioned the police while shouting at him.

It will be the correct form.

The thing is that Simple sentence has a subject, verb and a complete thought in a single sentence.

In this sentence, there were two different things that are happening that be a bit confusing so you need to make it in a mixed form.

Answer 2

Answer:

mentioning the police. she shouted at him.