It's hard to say without more code, but...
With the code you posted, when your
Globals.timeLeft value is
<= 0, you'll start processing the
else side of that code block. There, you set
Globals.timeLeft = 0, play some music, and do some other things.
Now, until something resets
Globals.timeLeft to a positive value again, every frame will process that
else block of code. So, it'll continue to set
Globals.timeLeft = 0, start playing your music again, and everything else there.
I'm not sure what the intent is here, but I assume you don't want to reprocess that
else block in every frame after your counter reaches 0 - which is what's happening now.