Robby was one of the students, he likes building stuff and he can be pretty chaotic, he is also afraid of the teachers(Miss Circle, Miss Thavel and Miss Bloomie), when the lights are on, it means that the teachers would stop killing students but when the lights are off, it means that the teachers would go kill every students except the good teachers(Miss Sasha, Miss Emily and Mister Demi), he is own building a respawn machine for those students who died while the lights are on

Robby: "this piece goes there! And that piece goes here!" building a respawn machine