Final answer:
Sergeant Major Morris threw the monkey's paw into the fire to protect others from the dangerous consequences of its use, as he had already suffered from its effects.
Step-by-step explanation:
The question refers to a character named Sergeant Major Morris from the short story The Monkey's Paw by W.W. Jacobs rather than any of the excerpts provided. Morris's motive for tossing the monkey's paw into the fire was to prevent others from suffering the consequences that come with using the paw to grant wishes.
Morris had experienced the paw's malevolent magic firsthand and understood the dangers associated with it; thus, he aimed to destroy it and stop further tragedy. Morris's actions reflect the story's themes of fate and the unintended consequences of tampering with destiny.