Mikey - Who's in the bag?

I've had this recurring dream (4 times now). I first had it about 3 years ago, and I had it again last night.

The dream is the same every time, and goes like this.

Mt Saint Helens is erupting, and has turned day into night. We must be close to it because I can see the red explosive ash behind us. We are in a truck, and Mikey is driving. We always have a third person but I can never tell who it is. He is driving frantically, but I soon realize he is not necessarily going AWAY from the moutain. I soon realize that he is trying to find a place to dispose of the body that I now see in the bed of the truck .. wrapped in a white sheet.

So my question is... Mikey - who's in the bag?