i think there are some missing lines about the rules :
- push the button in your right hand , let the drill "screw" you a little , then it will push the button under the bed , then both of you will be free .
- sensei : maybe i will be free , but i will also be dead because of the "screwing" .
- if you are lucky , you will have 1 % chance to live , lol . if you dont push the button , i will spare only your life , sensei , but i will kill your student girl .
- sensei : that is an easy choice to make .