You will die somewhat, again and again
I have a mind of my own.
Are you that desperate for his approval?
It's not Sammy. It's Ellicott, rooting around in his mind, calling forth anger and resentment. It's stuff Sam thinks for a split second, amped up and forced out.
But it's not Sammy. Dean listens—can't help but hear—and tries to reason with him. It's not Sam, though, so there's no one to reason with.
And it's not like Ellicott is making him say anything new. Sam's told him all this before, back when he was a snot-nosed punk of an eighteen-year-old, storming out to make it on his own. Dean refused to go with him and Sam lost it, screaming and crying and calling Dean nothing but a lap-dog with fangs and a gun.
It's Ellicott forcing Sam to speak, but they're all Sam's words.
The rocksalt hurts, but Dean'll heal. And Sam keeps talking, spurned on by a dead sadist.
Dean offers him his own gun, a test to see how awake Sam is in there.
And Sam pulls the trigger. Four times. Four damned times, just to be sure.
The non-existent bullets burn, cutting him open and making his soul bleed.
But Dean'll heal. He always does.