diff --git a/minefield.py b/minefield.py
index 014c0b8..a649f5a 100644
--- a/minefield.py
+++ b/minefield.py
@@ -91,19 +91,16 @@ class Minefield:
     # === MOVEMENT === #
     # ================ #
 
-    # check if sapper's destination is accessible if so then change position of the Agent
-    # If Agent comes upon a tile with a mine his starting position shall be reestablished 
+    # check if sapper's destination is accessible
+    # If Agent comes upon a tile with a mine his starting position shall be reestablished
     def is_valid_move(self, target_row: int, target_column: int):
-        if 0 <= target_row < const.V_GRID_VER_TILES and \
-                0 <= target_column < const.V_GRID_HOR_TILES:
-            if self.matrix[target_row][target_column].mine is None:
-                self.agent.position[0] = target_row
-                self.agent.position[1] = target_column
-            else:
-                self.agent.position[0] = int(self.agent.row)
-                self.agent.position[1] = int(self.agent.column)
-                ctypes.windll.user32.MessageBoxW(0, "Znowu się nie udało", "GAME OVER", 1)
-                # This part of the pop up message is just a temporary solution
+        if 0 <= target_row < const.V_GRID_VER_TILES \
+            and 0 <= target_column < const.V_GRID_HOR_TILES \
+                and self.matrix[target_row][target_column] is None:
+
+            return True
+
+        return False
 
     # distinguishes new mine's type and creates appropriate object
     def _create_mine(self, mine_data, row, column):