So I know this seems like a pretty minor scene, but somehow it really speaks volumes about something we already know: Dean will choose Sam over the entire world.
The sky is burning, angels are falling, people are in danger… but all that pales in comparison to the fact that Sam is dying.
So Dean’s gonna stay right there next to his brother, even though the world is ending again. Because no matter what happens, Sammy comes first.
"Don’t you dare think that there is anything, past or present, that I would put in front of you."