He is leaving the house vs He is going out of the house.

Hello teachers,
There is a set of drawings asking for different actions in present progressive, since Peter wakes up until he leaves the house, which is the next to the last picture. In the last picture he is getting on the bus to go to work.
My question:
As I’ve said the next to the last picture shows Peter leaving the house before going to work.
Which one is far more natural for that picture? Why?
a) He is leaving the house.
b) He is going out of the house.

I think is should be letter ‘a’ because the opposite of ‘leave’ is ‘arrive’. But I don’t know the reason. The dictionaries I’ve looked at, do not help me to clarify it completely.

Thanks in advance.

Yes, ‘leaving’ is more natural.
He is not just going out in order to stand outside. He is about to move away from it and go elsewhere.

Hello Beeesneees,
Thank you for your help and clarification.