Spirit Condemned?

I once worked, as a nurse, in an infamous Victorian prison in Liverpool. I was standing in a little room on the top floor or landing as they say, it is located between the two big wings. It was said to be where the condemned prisoners were led before execution. It was mid afternoon and I was counting some tablets. I felt someone brush past me, they were not rushing but they had purpose. I turned round to see who it was and no one was there. The landing was completely empty. Perhaps it was a funny twitch of my nervous system or perhaps not?