I just called a friend who was F/E on the Tu-154. He says the engine is near the tail cone. There is an S-Duct like in the 727.
He says in fact that all average non-pilot Russian know this because there was a famous "Airport" type movie in the USSR where a pilot cut through the rear bulkhead and into the S-duct from where he crawled out in flight. Of course totally impossible, but the guy was clearly shown crawling up the actual S-Duct during the movie.