I sensed the figure approaching me and held myself in readiness. Martial arts is one of my hobbies and while I wouldn't claim to be as expert as a Shaolin monk, I've got more than enough knowledge to be effective. As the intruder leaned towards me, I leaped up and pinned them to the wall.
The maid screamed.
'I'm terribly sorry,' I said, loosening my grip and helping her into a chair. 'I thought you were somebody else.'
The maid scowled. 'It is very hard working for you. The countess beat me all the time, but she never tried to kill me.'