Answer:
You can't.
Step-by-step explanation:
Not only is it dark, but there is nothing to stand on to reach the ceiling (which all depends if it's ceiling tiles or not), there is no window to break, or door to slam against. There is no way out. No one can let you out unless again the ceiling.
But even so I'm betting the ceiling is solid.
There is no way out unless you ya' know... died