Its the bossfight at the end of the mode on night 12. You win by looking at her through the cams as much as possible, this will stall her movement. At this point just survive until the end of the night.
Just keeping an eye on her no, you can literally get up to 4 am or so not looking at her before she goes in and kills you; still salty it wasnt a sex scene and just murder scene. Key thing is to keep sanity up so you can hear what goes on like goo room, bomb, or the electric switch.
THAT my friend the key is what the guy says about keeping doors locked and watch cameras, more or less when you find her you need to keep the camera on her.
