Another night, another nightmare.
He's worried. So he's watching over Sam, wishing he could chase the guilt away, hoping the advice given to Charlie could serve them too, refusing to let a damn secret be the third wheel.
The mirror is not only reflecting the horror they're chasing. He had a glimpse of what hasn't been said… yet. But Sam won't let him in.
"I'd die for you".
Dean won't push any further and withdraws in a painful silence. He's done that so many times, hiding behind his precious armor… How far is he ready to be left outside, again?
