Car shifted into gear when in park...

It's not like a motor. A motor has the full mark a few quarts above the oil pickup. An automatic has the oil pickup only slightly below the full mark. With a deep pan, if you have an extended pickup, only then does an auto have the same situation as a motor. A motor doesn't rely on oil to operate, but a trans is more like a floor jack in that respect. Pull the stick on a motor and it could show nothing but the motor will still run. Pull the stick on an automatic and it can show an inch or so of fluid and do nothing.