Start a game on Normal Mode. Now don't take ANY items. When you reach the 
front yard of the Police Station, run down the stairs to find Brad Vickers 
in zombie form. Kill him, then check his body for the Special Key. Now 
continue through the game to the Dark Room. Unlock the locker in the 
corner. Claire has 1 extra costume and 1 extra weapon, Leon has 2 extra 
costumes.