The CIA timeline published by the WSJ said the Ambassador and one other were dead when they retreated to the annex. So, what about the video of them pulling him out of a building and the story that a doctor struggled to save him but he died at the hospital?
Theres a full time line there.
Sean Smith died and was found before the retreat to the Annex. After the retreat, the Annex became the focus of the attacks and the compound was left pretty much to itself.
Later, after midnight, Stevens was found by supposed "looters" who say he was barely alive and they tried to get him to the hospital themselves and that he either died in route, or after getting there.