ER (1994) - 10x02 - The Lost

Carter reunites in the Congo with Charles and Gillian. Through flashbacks, we see Luka after Carter left 22 days before. He has caught malaria, and is soon captured by Mai Mai, who begin to murder the people he's with. Gillian introduces Carter to Debbie, a worker for the Red Cross. They search for Luka, and when finally shown the body, it's not even him. It turns out that a cross given to Luka by one of his patients led the Mai Mai to believe he was a priest. Carter, Debbie and Gillian find Luka, nearly dead, and put him on a plane back to Chicago. Carter gives him a letter to give to Abby and the news that he's going to stick around in the Congo for a while.