Sorry if this is old and been covered, but I downloaded the Bethune video to watch it frame, by frame, to look at the open door speculation. There are quite a few missing frames - the van is in the distance, and then a chunk of video is missing, and they are on top of it. Wonder if that was a glitch in the camera, or if it has been otherwise explained?
As for the door, it's impossible to tell, because there is a black artifact that moves around, but often is over the van. Looks like there's water or tree sap on the Bethune windshield that's right in the camera's line of the sight.