it sounds like a sleep disorder. i know of so many people who do/have done that kind of thing. they get up, eat food, use the bathroom, etc. some people even walk right out of their house and end up in random places. one of my sister's as a child did that and ended up on a neighbor's couch. my mom recently told me of her neighbor's adult son who becomes violent while sleep walking. some people can even have full conversations and appear to be awake but not remember anything.

it does not mean it's dissociation. you could get a sleep disorder evaluation if it is concerning you and happening a lot.