Dean Winchester (to Sam): We can’t save Cas if we’re stuck in some hospital. Just like I can’t strap on a time machine, go back and tell Cain to shove that Mark up his ass. Or stop you from releasing the Darkness. Now have we made mistakes? Yes, hell yes. And we can analyze each and everyone one of them over a couple of frosty’s when we are old and farting sawdust and out of this room!