[quote]Does he know you're awake? Did you make a sudden movement, gasp, or simply open your eyes?[/quote] The stranger has been observing you for a while and saw you open your eyes.

If he attacks immediately then I'll do what I can with my bare hands. If he continues to stand and stare I'll stretch casually (maybe hell think I think I'm dreaming or generally unsure of what I'm seeing) and reach for the weapon (pistol) I have beside me