--- Original:
.#.#
.#.#
.#.#
.#.#
.#.#
...#
.###
.#
.#################
)##..............##
.##.###.........@#
.##.###.....#
....<.....#
.........#
........#
........#
.......#
###...)#              ####
  ##..#               ###
 ###..#               ##
 #...#                #

--- Moving down one:

.#.#
.#.#
.#.#
.#.#
...#
.###
.#
.#################
)##..............##
.##.###..........#
.##.###.....@#
....<.....#
.........#
........#
........#
.......#
###...)#
  ##..#               ####
 ###..#               ###
 #...#                ##
 #.                   #

--- Moving left one

#.#.#
#.#.#
#.#.#
#.#.#
....#
#.###
#.#
#.#################
#)##..............##
#.##.###..........#
#.##.###.....@#
.....<.....#
..........#
.........#
.........#
........#
####...)#
   ##..#              ####
  ###..#              ###
  #...#               ##
  #.                  #

--- Entering from the right hallway.  The items are imposed over existing tiles
when they should not:

########.#####.#.#
.................#
########.#####.###
########.#   #.#
.........#   #.#################
##########   #)##..............##
             #.##.###..........#.
        ######.##.###.....#......
        #.........<.....#........
#########..............#.........
................@.....#..........
#########.............#..........
        #............#...........
        #########...)#)))))))))))
                ##..#............
               ###..#............
               #...#  ...........
               #.   .............
               ###############

---