Can you be in your country police officer and soldier?

Yes. You can be a member of the armed forces, and then go into the Reserves, which are a volunteer force. Reserve units can hold down normal jobs,(such as police officer), just as long as their employers understand that reserve military need to have two weeks off every year to freshen up their training, and that they may be called to active duty. They need an employer who will take them back in that eventuality.

I believe in the US, you cannot be an active-duty soldier and hold another job. You could, however, be a soldier, get out of the service, become of a police officer and then still be part of the National Guard. I think so anyway.

My only wonder is that in emergencies, sometimes NG soldiers get called up to help, but police would already be there and help, so not sure how that would work.

Volunteering and special divisions yes, but usually police and military do not cross over. It is usually different forces in military doing it

Thank you for best answer!

Yes! I wanna job of doctor in army!

Yes

Army has its own police MPs..