Or it seems so. I suspect the author's idea was to lure the mechanist into her own traps. Maybe that's why there are several musical instruments here. However they don't work. In any case, a couple of traps are not enough to kill the mistress. So I guess the most creative way to do it is to blackjack her and then throw her body into the fireplace. And then she dies screaming for a minute or so. Just think about it. A whole minute of screams from a dying woman burning alive. And you're just walking around grabbing the loot. Sounds fun? Well i really don't know. Maybe it's the most cruel Thief fan mission ever.