Dungeon game - allows players move out of board?

import random

BOARD = [(0, 0), (0, 1), (0, 2),
         (1, 0), (1, 1), (1, 2),
         (2, 0), (2, 1), (2, 2)]

def get_locations():
  monster = random.choice(BOARD)
  start = random.choice(BOARD)
  door = random.choice(BOARD)

  #If player, door or monster are random, do it all over again.
  if (start == monster or start == door) or (monster == door):
    return get_locations()

  return monster, door, start

def move_player(player, move):
  x, y = player
  if move == 'LEFT':
    y -= 1
  elif move == 'RIGHT':
    y += 1
  elif move == 'UP':
    x -= 1
  elif move == 'DOWN':
    x +=1
  else:
    print("That move doesn't exist PLEASE.")
  return x, y

def get_moves(player):
  moves = ['LEFT', 'RIGHT', 'UP', 'DOWN']
  if player[1] == 0:
    moves.remove('LEFT')
  if player[1] == 2:
    moves.remove('DOWN')
  if player[0] == 0:
    moves.remove('RIGHT')
  if player[0] == 2:
    moves.remove('UP')
  return moves

monster, player, door = get_locations()  

while True:
  moves = get_moves(player)

  print("Welcome to the dungeon! *evil laugh*")
  print("You are currently in room {}".format(player)) #fill in with player position
  print("You can move {}".format(moves)) # fill in with available positions
  print("Enter 'GIVEUP' to quit")

  move = input("> ")
  move = move.upper()

  if move == "GIVEUP":
      print("Giving up, you wait sadly for the Beast to find you. It does, and makes a tasty meal of you...")
      print("You lose.")
      break
  if player == door:
      print("You escaped, narrowly avoiding the Beast..")
      print("You win!")
      break
  if player == monster:
      print("You have been eaten by the Beast...")
      break
  if move in moves:
        player = move_player(player, move)
  else:
        print("Walls are hard, stop walking into them!")
        continue