script works in test mode but not when i play game?

mouse.KeyDown:connect(function (key)
    local key = string.lower(key)
    if string.byte(key) == 48 then
        local keyConnection = mouse.KeyUp:connect(function (key)
            if string.byte(key) == 48 then
                if used == false then
                used = true -- Run function
    Remote.RemoteEvent:FireServer()
    used = true
            for i = 1,5 do
            game.Workspace.CurrentCamera.FieldOfView = (70+(i*2))
            wait()
            end
            script.Parent.Boost.Whole.Fill:TweenSize(UDim2.new(0, 0,1, 0),"Out","Quad",5)
        script.Parent.Boost.Whole.Fill.Text = " "
            wait(5)
            for i = 1,5 do
            game.Workspace.CurrentCamera.FieldOfView = (80-(i*2))
            wait()
            end
            wait(3)
                script.Parent.Boost.Whole:TweenPosition(UDim2.new(.25,0,3,0),"Out","Quad",3.5)
            wait(3)
    script:Destroy()
    end
        end
        end)
    end
end)

Its not working! it works fine in studio but when I play in game nothing happens at all!