On starting point grab the key then tap the picture on desk 3 times to activate the mode , then leave immediately cause the other girl will spawn in the same room , if saiko catches you or hits you while going out , restart and try again.

Tips :

1-prioritize shoes and mask , you should be familiar with their spawn location now , mask is under one of the stairs and shoes can spawn in any shoes holder near exit or near classes.
mask can help when you bump into a sitting girl while being chased by other , and shoes can prevent damage in case a girl entered a class room you are in if she broke the glass.

2-you will be hiding alot in this run - i found myself hiding alot under the stairs and in the closet next to the power box , try to avoid chase as it can consume the mask and your time , this run can take up to 30 min.

3-be patient , always walk unless being chased , do not let RNG provoke you , just search the room for key and move for next one.

4-so you don't get confused , the ending will be similar to the normal extreme yangire mode , the second you open the safe , on of the girls will knock you out , after waking up she'll tell you that she'll let you go if win a game , win a game of rock paper scissors then follow her to the exit and take key.