My Gun is damaging Pathfinding NPCs, but its not killing them?

So I'm using a raycasting gun and when I fire it at a NPC , the NPC reaches 0 health but doesnt die and keeps following me? Here is the scripts. Oh and by the way they are holding a sword because they are ninjas.

  local tool = script.Parent
    local player = game:GetService("Players").LocalPlayer
     
    tool.Equipped:connect(function(mouse)
    	print("Tool equipped!")
     
    	mouse.Button1Down:connect(function()
    		print("Mouse pressed!")
    		local ray = Ray.new(tool.Handle.CFrame.p, (mouse.Hit.p - tool.Handle.CFrame.p).unit * 300)
    		local part, position = workspace:FindPartOnRay(ray, player.Character, false, true)
     
    		local beam = Instance.new("Part", workspace)
    		beam.BrickColor = BrickColor.new("White")
    		beam.FormFactor = "Custom"
    		beam.Material = "Plastic"
    		beam.Transparency = 0.6
    		beam.Anchored = true
    		beam.Locked = true
    		beam.CanCollide = false
     
    		local distance = (tool.Handle.CFrame.p - position).magnitude
    		beam.Size = Vector3.new(0.3, 0.3, distance + 5)
    		beam.CFrame = CFrame.new(tool.Handle.CFrame.p, position) * CFrame.new(0, 0, -distance / 2)
     
    		game:GetService("Debris"):AddItem(beam, 0.1)
     
    		if part then
    			local humanoid = part.Parent:FindFirstChild("Humanoid")
     
    			if not humanoid then
    				humanoid = part.Parent.Parent:FindFirstChild("Humanoid")
    			end
     
    			if humanoid then
	                script.Parent.Fire:Play()
    				    				humanoid:TakeDamage(40)

    			end
    		end
    	end)
    end)

Thanks!