In the culminating moment of the tale, it is as if all the forces of the "little metropolis" are joined both in ridiculing Major Molineux and in inviting Robin's complicity. That he does not resist, that he's overcome with "a sort of mental inebriety," which leads to his spontaneous and heartfelt shout of laughter which was the loudest of all, allows the reader as well as Robin's urbane companion to understand that Robin has chosen to ally himself with the mob of fiends.
He was an elderly man, of large and majestic person, and strong, square features, betokening a steady soul; but steady as it was, his enemies had found means to shake it. His face was pale as death, and far more ghastly; the broad forehead was contracted in his agony, so that his eyebrows formed one grizzled line; his eyes were red and wild, and the foam hung white upon his quivering lip. His whole frame was agitated by a quick and continual tremor, which his pride strove to quell, even in those circumstances of overwhelming humiliation. But perhaps the bitterest pang of all was when his eyes met those of Robin; for he evidently knew him on the instant, as the youth stood witnessing the foul disgrace of a head grown gray in honor. They stared at each other in silence, and Robin's knees shook, and his hair bristled, with a mixture of pity and terror. Soon, however, a bewildering excitement began to seize upon his mind; the preceding adventures of the night, the unexpected appearance of the crowd, the torches, the confused din and the hush that followed, the spectre of his kinsman reviled by that great multitude, all this, and, more than all, a perception of tremendous ridicule in the whole scene, affected him with a sort of mental inebriety. At that moment a voice of sluggish merriment saluted Robin's ears; he turned instinctively, and just behind the corner of the church stood the lantern-bearer, rubbing his eyes, and drowsily enjoying the lad's amazement. Then he heard a peal of laughter like the ringing of silvery bells; a woman twitched his arm, a saucy eye met his, and he saw the lady of the scarlet petticoat. A sharp, dry cachinnation appealed to his memory, and, standing on tiptoe in the crowd, with his white apron over his head, he beheld the courteous little innkeeper. And lastly, there sailed over the heads of the multitude a great, broad laugh, broken in the midst by two sepulchral hems; thus--
"Haw, haw, haw--hem, hem--haw, haw, haw, haw!"
The sound proceeded from the balcony of the opposite edifice, and thither Robin turned his eyes. In front of the Gothic window stood the old citizen, wrapped in a wide gown, his gray periwig exchanged for a night-cap, which was thrust back from his forehead, and his silk stockings hanging down about his legs. He supported himself on his polished cane in a fit of convulsive merriment, which manifested itself on his solemn old features like a funny inscription on a tomb-stone. Then Robin seemed to hear the voices of the barbers, of the guests of the inn, and of all who had made sport of him that night. The contagion was spreading among the multitude, when, all at once, it seized upon Robin, and he sent forth a shout of laughter that echoed through the street; every man shook his sides, every man emptied his lungs, but Robin's shout was the loudest there.