As Sam stayed behind to draw the Rabids away, using himself as bait to find a cure for the infection spreading through his own veins, Dean escorted Jenna and the infant to safety.
Dean swung a tire iron, the metal clanging against her skull, but she didn't drop. It took three more hits to ground her. He stood over her, chest heaving. "These aren't demons, Sammy. They’re 'Rabids.'" [S11E1] Out of the Darkness, Into the Fire
The black smoke that had roared across the landscape was gone, leaving behind a stillness that felt like a trap. Dean wiped a smear of blood from his forehead, his eyes darting to the tree line. He could still feel the phantom touch of the woman in the black dress, the Mark of Cain gone from his arm but the weight of her words settled deep in his marrow. "Sam," Dean rasped, his voice cracking. "You okay?" As Sam stayed behind to draw the Rabids
In the quiet of a darkened hallway, Dean looked down at the baby. He felt a pull, a strange, magnetic tether he couldn't explain. He moved the infant’s blanket aside, and his heart stopped. There, on the baby's tiny shoulder, was the mark. The Mark of Cain. He stood over her, chest heaving