if you pick up a gun, walk into a different room and shoot then it is premeditated. It doesn't mean thinking and planning for months, it could be seconds. It just means that it is a deliberate act.
So what would count as murder that was not premeditated, as opposed to manslaughter then?
I thought premeditated required the person to have reasonably thought about what they were doing.
If it was a violent argument where he started waving a gun around, and shot in the heat of the moment without really thinking about what he was doing, would that really pass as being premeditated in a court of law?