OK.
Will the vehicle be on your drive, or on private land ?
I have a vague recollection, that I read somewhere, that if you do this on a public road, or public place you will be committing an offence.
I have an earlier vehicle with the smart fob option.
If I walk away with the smart key fob all the doors will lock.
I have never tried this with the engine running !
If I use the normal remote key for the ignition, and have the smart key with me; it could be possible, but I have not tried this either.
However, these vehicles are so smart (pun intended), it would not surprise me if the vehicle would 'intervene'.
Somewhere in this forum there is a thread regarding 'remote starting' which, it would appear, is what you are trying to achieve.
The search box is on your home page, top right corner.
Good Luck.