Here's the green...
That last cap is cool because you can see Dean reflected in the glass.
People have commented on how the film shots of the guys and kids in the car linked Dean with the older boy, Joe, and Sam with Ryan. They also played it up with the way the kids were dressed with Joe in layers and a jacket like Dean and Ryan in a shirt and hoodie like Sam was a lot early in the show. They continued it by marking up Ryan's face with blood in the same way they did with Sam when he was drinking demon blood.
Some people have done metas about maybe red being for hell and blue for heaven with green indicating lies and wrongness and yellow being danger. There was hardly any blue at all except for what people were wearing, mostly Dean, Sam and Bobby. What blue Cas has on is covered in blood in pretty short order.
Caps from
crystalcaps.