diff --git a/mods/lzr_laser/physics.lua b/mods/lzr_laser/physics.lua
index f1ad9fe..4d86cff 100644
--- a/mods/lzr_laser/physics.lua
+++ b/mods/lzr_laser/physics.lua
@@ -105,11 +105,13 @@ function lzr_laser.add_laser(pos, dir, varea, vdata)
 		if detected then
 			local def = minetest.registered_nodes[nodename]
 			local active = def._lzr_active
-			-- Activate node
-			vdata[vi] = minetest.get_content_id(active)
-			local done = lzr_laser.check_detectors_in_area(lzr_globals.PLAYFIELD_START, lzr_globals.PLAYFIELD_END)
-			if done then
-				lzr_levels.next_level()
+			if active then
+				-- Activate node
+				vdata[vi] = minetest.get_content_id(active)
+				local done = lzr_laser.check_detectors_in_area(lzr_globals.PLAYFIELD_START, lzr_globals.PLAYFIELD_END)
+				if done then
+					lzr_levels.next_level()
+				end
 			end
 		end
 		-- Laser ends here
@@ -164,37 +166,30 @@ function lzr_laser.travel_laser(pos, dir, varea, vdata)
 end
 
 -- Remove all lasers in area and disable all laser blocks
-function lzr_laser.clear_lasers_in_area(pos1, pos2, ignore_emitters)
-	-- Remove lasers
-	local lasers = minetest.find_nodes_in_area(pos1, pos2, {"group:laser"})
-	minetest.bulk_set_node(lasers, {name="air"})
-
-	-- Disable laser blocks (mirror, etc.)
-	local laser_blocks = minetest.find_nodes_in_area(pos1, pos2, {"group:laser_block"})
-	for b=1, #laser_blocks do
-		local block_pos = laser_blocks[b]
-		local block = minetest.get_node(block_pos)
-		local def = minetest.registered_nodes[block.name]
-		local is_ignored_emitter = false
-		if ignore_emitters ~= true then
-			is_ignored_emitter = minetest.get_item_group(block.name, "emitter") > 0
-		end
-		if def and not is_ignored_emitter then
-			local inactive = def._lzr_inactive
-			if inactive then
-				minetest.set_node(block_pos, {name=inactive, param2=block.param2})
+function lzr_laser.clear_lasers_in_area(pos1, pos2, ignore_emitters, varea, vdata)
+	for vi=1, #vdata do
+		local cid = vdata[vi]
+		local nodename = minetest.get_name_from_content_id(cid)
+		if minetest.get_item_group(nodename, "laser") ~= 0 then
+			vdata[vi] = minetest.CONTENT_AIR
+		elseif minetest.get_item_group(nodename, "laser_block") ~= 0 then
+			local def = minetest.registered_nodes[nodename]
+			local is_ignored_emitter = false
+			if ignore_emitters ~= true then
+				is_ignored_emitter = minetest.get_item_group(nodename, "emitter") > 0
+			end
+			if def and not is_ignored_emitter then
+				local inactive = def._lzr_inactive
+				if inactive then
+					vdata[vi] = minetest.get_content_id(inactive)
+				end
 			end
 		end
 	end
 end
 
 -- Emit lasers from all active emitters
-function lzr_laser.emit_lasers_in_area(pos1, pos2)
-	local vmanip = minetest.get_voxel_manip(pos1, pos2)
-	local vpos1, vpos2 = vmanip:get_emerged_area()
-	local varea = VoxelArea:new({MinEdge = vpos1, MaxEdge = vpos2})
-	local vdata = vmanip:get_data()
-	local vdata_p2 = vmanip:get_param2_data()
+function lzr_laser.emit_lasers_in_area(pos1, pos2, varea, vdata, vdata_p2)
 	local emitters = minetest.find_nodes_in_area(pos1, pos2, {"group:emitter"})
 	for e=1, #emitters do
 		local epos = emitters[e]
@@ -206,10 +201,6 @@ function lzr_laser.emit_lasers_in_area(pos1, pos2)
 			lzr_laser.emit_laser(emitters[e], varea, vdata, vdata_p2)
 		end
 	end
-
-	vmanip:set_data(vdata)
-	vmanip:set_param2_data(vdata_p2)
-	vmanip:write_to_map()
 end
 
 -- Return true if all detectors in area are on (including if no detector)
@@ -228,6 +219,16 @@ end
 
 -- Completely recalculate all lasers
 function lzr_laser.full_laser_update(pos1, pos2)
-	lzr_laser.clear_lasers_in_area(pos1, pos2)
-	lzr_laser.emit_lasers_in_area(pos1, pos2)
+	local vmanip = minetest.get_voxel_manip(pos1, pos2)
+	local vpos1, vpos2 = vmanip:get_emerged_area()
+	local varea = VoxelArea:new({MinEdge = vpos1, MaxEdge = vpos2})
+	local vdata = vmanip:get_data()
+	local vdata_p2 = vmanip:get_param2_data()
+
+	lzr_laser.clear_lasers_in_area(pos1, pos2, nil, varea, vdata)
+	lzr_laser.emit_lasers_in_area(pos1, pos2, varea, vdata, vdata_p2)
+
+	vmanip:set_data(vdata)
+	vmanip:set_param2_data(vdata_p2)
+	vmanip:write_to_map()
 end