Read at your own risk

 - Check the door
 - Wait until the lights out
 - Check the table
 - Wait a little
 - After the steps, check the window
 - After the crow, go to bed
 - After wake up, check the wall, next to your bed
 - Wait a little, and check the hole on the wall
 - Behind the locker, you can find a coin, pick it up
 - Go to the ventillation hole, and check it
 - Disgusting, but eat the rat
 - More disgusting, but check your vomit
 - Check the door