Help with this function?

I created a function that counts down from argument to another then uses the wait method to wait until it's complete,but it won't continue with thread once its done.Why and how do I manage to fix it?

function Countdown(StartTime,EndTime)
-------------------------------------
	local Library = assert(LoadLibrary("RbxUtility"))
	local Signal = Library.CreateSignal()
-------------------------------------
	for i = StartTime,EndTime do
		print(i)
		if i == EndTime then
			Signal:fire()
			return Signal:wait()
		end
	end
end

Countdown(1,10)
print('Countdown Finished')
print('yay')