diff --git a/maps/mountain_fortress_v3/functions.lua b/maps/mountain_fortress_v3/functions.lua
index d6d9d2e4..6c41cfd6 100644
--- a/maps/mountain_fortress_v3/functions.lua
+++ b/maps/mountain_fortress_v3/functions.lua
@@ -420,7 +420,7 @@ local function do_replace_tiles_slowly()
         return
     end
 
-    for _ = 1, 300 do
+    for _ = 1, 1000 do
         local tile = table.remove(tiles_to_replace, #tiles_to_replace)
         if tile and tile.valid then
             surface.set_tiles({ { name = 'water-shallow', position = tile.position } }, true)
@@ -983,16 +983,16 @@ function Public.find_void_tiles_and_replace()
     local rp = Collapse.get_reverse_position()
 
     local area = {
-        left_top = { x = (-zone_settings.zone_width / 2) + 10, y = cp.y },
-        right_bottom = { x = (zone_settings.zone_width / 2) - 10, y = rp.y }
+        left_top = { x = (-zone_settings.zone_width / 2) + 10, y = -rp.y - 1000 },
+        right_bottom = { x = (zone_settings.zone_width / 2) - 10, y = cp.y }
     }
 
     local adjusted_zones = Public.get('adjusted_zones')
 
     if adjusted_zones.reversed then
         area = {
-            left_top = { x = ((zone_settings.zone_width / 2) + 10) * -1, y = rp.y },
-            right_bottom = { x = math.abs((-zone_settings.zone_width / 2) - 10), y = cp.y },
+            left_top = { x = ((zone_settings.zone_width / 2) + 10) * -1, y = cp.y },
+            right_bottom = { x = math.abs((-zone_settings.zone_width / 2) - 10), y = rp.y },
         }
     end
 
diff --git a/modules/explosives.lua b/modules/explosives.lua
index 8acb4b58..9b33443c 100644
--- a/modules/explosives.lua
+++ b/modules/explosives.lua
@@ -213,6 +213,7 @@ local function damage_area(cell)
     end
 
     local tile = surface.get_tile(cell.position)
+    if not tile or not tile.valid then return end
     if this.explosives.destructible_tiles[tile.name] then
         local key = pos_to_key(tile.position)
         if not this.explosives.tiles[key] then