Any ideas for a one-man shortfilm?

i got a cool story that I just came up with after reading your question.

-- all of the sudden, a man / boy / women whoever the actor is , awakes in the middle of an empty room. there are no doors and is closed and celied by all sides except by a tiny window on the wall. the person suddenly starts walking around and asks if anyone is outside "example : is anyone out there?" he then starts shouting out the window but noone can hear him. also, for some weird/reason he cant remember anything. hhe suddeny starts going crazy and randomly starts hitting on the wall and keeps screaming out of the window. he tries to escape but its locked. He suddenly hears a loud scream (creepy) and gets scared. he brakes the window with his bare hands (and bleeds with the broken glass) and almost escapes until he miserably falls down. he looks out the window and notice something. he rans out to the farthest corner of the room and tries to hide. camera closes up to him (his face in shock and horror) and the light slowly fades out and when it comoletely turns dark, the person screams in horror(we cant see anything btw) after a creepy voice says "you are the only one left"

the end