Timer GUI Localscript Roblox Studio

--[[
Layout:
TimerGui
 - Frame
  -Localscript
  -StartTimer
  -EndTimer
  -TextLabel

StartTimer and EndTimer are BindableEvents
]]--
local startTimer = script.Parent.StartTimer
local endTimer = script.Parent.EndTimer
local gui = script.Parent
local text = script.Parent.TextLabel

local function timeToString(seconds)
    local minutes = math.floor(seconds / 60)
    local seconds = tostring(math.floor(seconds - (minutes * 60))
    )
    minutes = tostring(minutes)
    if string.len(minutes) == 1 then
        minutes = "0"..minutes
    end

    if string.len(seconds) == 1 then
        seconds = "0"..seconds
    end

    return minutes..":"..seconds

end
startTimer.Event:Connect(function(seconds)
    gui.Visible = true

    local startTime = os.clock()
    while os.clock() - startTime < seconds  do
        text.Text = timeToString(seconds - (os.clock() - startTime))
        wait()
    end

    endTimer:Fire()
    gui.Visible = false

end)