Mr. White has figured out the whatever is on the other side of the door should rightfully be sent back to the grave. By the time that Mr. White makes the first wish for 200 pounds and makes the last wish for Herbert, or whatever is behind the door to return to the grave, he has figured out that the monkey's paw is an instrument of dark magic.
Mr. White realizes that whatever form Herbert is in on the other side of the door, it does not belong out of the grave. The man was crushed by a machine, he is terrified at what the wish might have done to reconstruct a form of Herbert.
Although Mr. White had given in to Mrs. White's pleading to make a second wish on the monkey's paw to bring Herbert back, when he does not return immediately, Mr. White becomes suspicious. He realizes that with his son dead for ten days, he cannot imagine what kind of monster is really at the door.
"For God's sake, don't let it in," cried the old man trembling. (Jacobs)
"You're afraid of your own son," she cried, struggling. "Let me go. I'm coming, Herbert; I'm coming." (Jacobs)
The first wish that Mr. White makes is for 200 pounds. Unpon making this wish, he initially does not think that it will come true. The very next day he and his wife receive a call from their son's employer, Maw and Meggins. They are told that their son had been caught in the machinery at work and was killed; they are then told that they would be getting 200 pounds as compensation for their son's death.
A little over a week later, Mrs. White wakens in the middle of the night with what she thinks is a brilliant idea -- she is going to make a second wish using the monkey's paw because, as she states, "We've only had one." To this Mr. White responds, "Wasn't that enough?" At this point it is clear that he realizes that anything that they wish for using the paw will be gotten only if something bad or evil happens. Mrs. White ignores her husband and proceeds to wish her son alive again. Mr. White knows that if the son comes back he will look as he did when he was killed and mutilated in the machinery and since he has, at this point, been dead for ten days, it will not be a pretty sight. Therefore, he refuses to open the door when they hear the knock and makes his final wish -- probably wishing for their son, Herbert, to be dead again. So, he does not answer the door because he believes that his son will be a dead, mutilated body.
why does sergeant Morris think the monkey paw is dangerous