John, in his car,

Are these sentences correct:

[color=red]1-John, at the office, is a friendly fellow; but in his car, he becomes very aggressive.
Meaning: John, when he is at the office, is a friendly fellow. But in his car, he becomes very aggressive.

[color=indigo]2-Jeff, at school, is very well-behaved, but at home, he is pretty noisy and cheeky.

Gratefully,
Navi.

As an exercise it’s okay, but in everyday usage it would sound convoluted. The fact that you have felt obliged to provide a ‘meaning’ indicates that most people would use an alternative more similar to that meaning!

Very good point!
Thank you very much Beeesneees.