"Oh, I won't give up," Dean replies easily. "But I don't think I'm gonna walk away from Lucifer alive if the Colt doesn't work."

Dean's fully prepared to die, whether he succeeds or not. He figures even if he manages to shoot and successfully kill the devil, his cronies will take him down regardless. Dean figures it'll be the end either way — for him, at least.

Which is the price someone has to pay.

"But knock yourself out. Do all the research you want."

Dean has done enough over the years to convince him that the Colt is the only way, which is why he places so much stock in that plan.

He glances up in the rear view mirror, trying to get a glance at Sam's eye. "Give it a few days, let the swelling go down. Everything else healed up for the most part." Sam was a wreck after the beating he took — and now look at him.

Not that Dean would put it past Lucifer to leave a souvenir like that — but he thinks there's a possibility Sam will regain his eyesight.