There's kinda a 'nothingness' in his eyes. BUT, I could be projecting because we now know what we now know, hindsight is 20/20.

I know a lot of people with that “nothingness” in their eyes. It looks like depression to me.

Or, he's just having a moment of being at peace, and not thinking. We all have those moments. It would be hell if we were all called psychopaths just because we had two seconds of 'nothingness' in our look. LOL! 

Oh, and yeah, depression does that too.

Lack of emotion: Aquarius???

I think lack of emotion or lack of access to emotions has a lot to do with it.

Take a look at Ed Gein’s birth chart...here you go

Moon on the DC .. Jeffery Dahmer also has Moon on the DC. Here is Jeffery Dahmers chart

AND they both have Moon square Saturn.  Your lack of access to emotion theory sounds about right.