It was that the sight of Sam unconscious sort of obliterated that she was speaking. He did hear her, but the words didn't register. He would've agreed with her, mostly. Gruffly.
"Sam!"
Often, Dean had time to realize, after doing things like shouting his baby brother's name, that he shouldn't have done them. That they were putting him in danger, or his brother in danger.
Or his daughter in danger.
He held up his hand to Mary and was starting to go to Sam when he was shot. He saw the dart in his chest and looked over at where it'd come from.