Thank you for voting this in Superchiow, Catherine, hectatess, Kathy, NoilyPrat, and SpnKs15.
It was when the cage opened everything changed.
To be fair though, that's obvious that when Lucifer is set free that things will be different.
The opening of the cage didn't just change the world however, it changed Sam. In that moment all the forgotten memories of heaven and an older brother who was much more loyal to his father than Dean had ever been, and Sam had complained about him yeesh Dean couldn't even hold a candle to Michael-
But anyway. Sams, or should I say Lucifers memories returned to him in a moment of sudden clarity and he only had three thoughts right now.
One, He couldn't destroy humanity like he had been planning.
Two, under no circumstances could he tell Dean his true identity.
And three, they needed to get out of here before the cage sucked them (especially Dean) in.
So the former angel that now went by Sam did the first thing he could think of and teleported them out of there.
Onto a plane. When Dean had a fear of flying.
Dean looked at 'Sam' slightly panicked.
"What the heck just happened?"