As always, he chooses Sam.
Dean turns his back on the box and kicks down the bathroom door. He quickly grabs his brother and the keys to the car, pulling a half-naked Sam behind him. Sam tries to fight him, but Dean is just stronger and he easily gets Sam in the car.
He’s out of the motel parking lot before Sam can even get a hand on the door.
“Where are you taking me? Why did you pull me out of there so fast - without clothes, mind you - if you’re NOT one of them!” Sam tries not to sound scared. But Dean hears it. He knows. Sam thinks he’s another shifter. He takes a deep breath.
“To prove I’m really Dean. Your Dean. I’m not a shifter, I promise. I would never ever hurt you Sammy. I’m sorry I scared you.”
Dean doesn’t mention the box. Doesn’t mention he pulled Sam out of their over his fear of the box. He’s glad he didn’t even open it. Whoever knows he was there is not someone he wants a package from.
Sam’s completely avoiding eye contact, pulling as far away from Dean as he can.
“Sammy? What happened? What did they do to you?”
“Like you don’t know.” Sam still can’t face him.
“I don’t know, Sam! How can I prove to you I would never ever hurt you! I love you! I’m your Dean, I truly am!”
Sam takes a breath and looks up at Dean. “There is one thing you could do.”