
In chapter V, when the boys return from their holidays, Grey takes up with Mallett, who is disliked by all the other boys because of his superior attitude. The boys endure Mallett's treatment of them as long as they could until one day they conspire to get back at Mallett and Grey. Right after the bell rings for class to begin, they bar the classroom door so that Mr. Dallas can't get in. Then four boys jump on Mallett and four attempt to jump Grey. However, Grey gets on top of his desk and aims a pistol at them:
"Not an inch nearer, Smith, or I fire. Let me
not, however, baulk your vengeance on yonder hound: if I could suggest any refinements in torture, they would be at your service." Vivian Grey
smiled, while the horrid cries of Mallett indicated that the boys were "roasting" him. He then walked to the door and admitted the barred-out
Dominie. Silence was restored. There was an explanation and no defence; and Vivian Grey was expelled.
No explanation is given for why Grey is expelled, but we can guess it is because he had a gun.