Place a block when you click?

I'm trying to make it so when you click a gui, a brick follows your mouse, and if you click again, the brick stops following your mouse. Why won't this work?

It's a localscript.

This is what I have:

player = game.Players.LocalPlayer
mouse = player:GetMouse()

function run()
	script.Parent.TestValue.Value = true
	
	local test = game.ReplicatedStorage.BuildItems.Test:clone()
	test.Parent = game.Workspace
		while true and script.Parent.TestValue.Value == true do
		wait()
		test.Position = Vector3.new(mouse.Hit.p.X,0.5,mouse.Hit.p.Z)
		mouse.Button1Down:connect(function()
			--script.Parent.TestValue.Value = false
			break -- something is wrong with this
		end)
		
	end
end

script.Parent.MouseButton1Down:connect(function()
	run()
end)