Thank you Kandilyn for commenting! Oh, and I'm glad you smiled but you won't for long sorry not sorry MWAHAHAHAHA
Sam broke out of the panic room, and Dean chased him down.
Dean tried to stop him, but Sam needed to do this. He needed to stop Lilith.
But Dean wouldn't listen, wouldn't trust him to do this, so he did the only thing his Demon Blood High mind could think of.
He strangled Dean.
He knew he'd come back so it wasn't that big of a deal.
I mean, don't get him wrong, he feels guilty as heck but still, it wasn't like Dean was ACTUALLY DEAD.
Right?
He came back heartbroken and guilty, wanting to cry to Dean even if he would only be yelled at.
Dean was right and he screwed up big time.
So he was expecting a large range of different ways this would play out.
He didn't expect Dean to still be there dead on the floor when he came back though.
He waited for hours for Dean to come back so he could apologize, but he did not wake up.
It was the next day, but Dean did not wake up.
Sam stayed there with no food and little sleep for a week, but still, nothing.
The authorities finally came in, saw Sam next to the body, and despite his struggles to stay with his brother (he couldn't be dead, he COULDN'T) he was thrown in jail.
He stayed there the rest of his days, and even in heaven, he could not find Dean.