Remote Event Firing Multiple Times?

When a brick is clicked in my game, it fires a remote event, and an item is added to the players inventory (the inventory is a custom one I made). Here's the script in the brick:

function onClick(plr)
    script.Parent:Destroy()
    local event = Instance.new("RemoteEvent")
    event.Parent = plr.Backpack
    event.Name = "TestShroomAdd"
    event:FireClient(plr)
    print("!")
end

script.Parent.ClickDetector.MouseClick:connect(onClick)

and here's the script in the players Backpack:

local event = script.Parent.Parent:WaitForChild("TestShroomAdd")

event.OnClientEvent:connect(function()
    print("!")
    if game.Players.LocalPlayer.PlayerGui.Inventory.Frame.slotone.Value ~= true then
        game.Players.LocalPlayer.PlayerGui.Inventory.Frame.slot_one.Object.Value = "testshroom"
        game.Players.LocalPlayer.PlayerGui.Inventory.Frame.slot_one.Text = "TestShroom"
        game.Players.LocalPlayer.PlayerGui.Inventory.Frame.slotone.Value = true
    elseif game.Players.LocalPlayer.PlayerGui.Inventory.Frame.slottwo.Value ~= true then
        game.Players.LocalPlayer.PlayerGui.Inventory.Frame.slot_two.Object.Value = "testshroom"
        game.Players.LocalPlayer.PlayerGui.Inventory.Frame.slot_two.Text = "TestShroom"
        game.Players.LocalPlayer.PlayerGui.Inventory.Frame.slottwo.Value = true
    end
end)

Note: script in the backpack is a Local Script.

now, the problem. If there are two bricks, and I click on each of them, the Remote Event only fires once. Each brick is exactly the same, same script (the first script I mentioned), same everything, however the first brick I click on fires the event, and it gets added to the players inventory, however the second brick I click does fire the event (as far as I know), however the script in the players backpack does not react to the event being fired. Any help?