I think what happend was that when Jamie was shot in his time Sapling was injured in someway too but Sapling must have died ! so Jamie took Saplings place although he was still unconscious or dieing ! but Jamie's body must have died in his time whilst his mind was in the past ! so when his mind came back it came back to a dead body but the old lady summoned a spirit that came as an eagle and resuscitated him !
(complicated, I know)