For those who are struggling with this game i have some tips for you. (note these are thing that i've noticed but may or may not be a thing)
1: use windows: i don't think she will immediately see you through a window unless she's actively looking through it. use this to scope out the halls before you leave rooms.
2: Her little "gifts": sometimes when you're attacked and escape she will switch personalities and start saying "sorry" at which point if you stay near her she will offer you a healing item. my rule of thumb is only accept that once, after that you run the risk of it being poisoned.
3: Poison: you will not notice an effect right away, at some point you will see "i feel dizzy" on the screen. at that point hightail it to the starting room and grab the antidote on the desk. (i don't know what happens if you succumb to the poison)
4: The "nice" personality: after she gives you a healing item DO NOT LET HER OUT OF YOUR SIGHT, she will be trying to get behind you and out of eyesight, if she succeeds, she will knock you out, drag you into a room, then lock the door. the key will always be in the room with you but she will stand and wait outside the door.
5: put some damn shoes on: her favorite thing to do upon spotting you is but the windows on the rooms exit door. glass can be safely passed over if you're crouching, any thing else will hurt you. in one of the class room hallways there will be a pair of shoes you can grab that makes you immune to glass. (i highly recommend making these one of the first things you grab)
that about all i can think of at the moment but hopefully this lets you survive a little longer on your next run. Good Luck.