The 319 does indeed have such an overwing exit with a slide unfolding over the trailing edge. The 320 has 2 such exits on each side.
The slides come down inboard of the engine and are usually well clear of the hot metal. A passengers natural momentum would carry them well away to the rear, also the evacuation would normally start only once the engine was shut down.
The BA 318 does NOT have an overwing exit.
Last edited by busTRE; 24th May 2013 at 19:15.