Location: Main House, in the second floor Rec Room, on the central counter.
Guide: Find yourself in Mia's shoes, trying to evade Marguerite. Rush across the bridge and through the double doors.
The open door to your right is just a taunt, instead bear left, and through a couple rooms filled with mold and televisions. The candles start to go out as you reach the far door, but they aren't directly threat-related. Note the crate immediately visible as you exit the TV room. As soon as you pass it, Marguerite will enter the corridor from the left.
Sneak back behind the crate until she's passed through the right door, then sneak left, the way she came in. Go past the shadowy plinth on to the balcony and go right, hiding in the corner until Marguerite has come and gone. Return to the plinth and turn the shape so that its shadow matches the spider on the wall. Press F when you're close as you can get, and the wall opens.
Scoot through this narrow passage into a new area. Note the small pile of pallets and other miscellaneous refuse ahead of you. When Marguerite inevitably comes in through the far left door, hide behind this stack. Keep it between you and her until she moves toward the door you entered by. Sneak forward then turn right, and drop into the hole here.
Follow the tunnel and examine the objects here, which will trigger a sudden darkness, ambush, and Mia being dragged off to some gruesome fate or another. She does get to kick Marguerite in the face, which is nice.
Despite the ending, making it this far in the tape does unlock the 'Can't Catch Me' achievement.