Theory:

6. I got up, paced up and down the room. Then another lovely thought struck me. I would marry. I would get married to a woman doctor who had plenty of money and a good medical practice. She had to be fat; for a valid reason. If I made some silly mistake and needed to run away she should not be able to run after me and catch me!
 
     With such thoughts in my mind I resumed my seat in the chair in front of the table. There were no more sounds from above. Suddenly there came a dull thud as if a rubber tube had fallen to the ground ... surely nothing to worry about. Even so I thought I would turn around and take a look. No sooner had I turned than a fat snake wriggled over the back of the chair and landed on my shoulder. The snake’s landing on me and my turning were simultaneous.
Explanation:
 
The doctor then got out of his chair and began strolling back and forth in the room before deciding on one more thing. He chose to marry a wealthy woman doctor who had a successful medical practice. His mind was obsessed with his appearance, marriage, and future plans as he was young and unmarried.
 
He was so proud of himself for being attractive, young, and a doctor by profession that he didn't even notice the repetitive sounds he was hearing. The doctor also imagined himself marrying a fat woman. He had a valid reason for it as well. He reasoned that if he made a mistake and his wife became enraged and decided to chase him down to hit him, she would not be able to run fast enough to catch him if she was fat. The doctor sat back in his chair once again, thinking about all of these things.
 
The noise had stopped at that point, but then something fell down with a thump. It seemed like a rubber tube had fallen, but the doctor was unconcerned because his mind was filled with dreams and ideas about his own self-improvement (appearance) and marriage life. He did not realise the seriousness around him. Though he was least bothered by the thing that had fallen down, he thought to turn around to see what it was. As soon as the doctor turned, he saw that a big fat snake had crawled over the chair and sat on his shoulders. The timing of the doctor’s turning around and the snake’s landing on his shoulder was the same. The doctor's carelessness had finally landed him in trouble.
 
King Cobra.png
Cobra snake
 
Meaning of difficult words:
 
S.No
Words
Meaning
1.
Struck  To came into someone's mind suddenly
2.
Valid
Based on a logic
3.
WriggleTo twist and turn your body with quick, short movements
4.
Simultaneous
Happening at the same time as something else
5.
Plenty A large amount/ a lot
6.
ThudA low sound made by something heavy falling
Reference:
National Council of Educational Research and Training (2006). Beehive. The Snake and the Mirror - Vaikom Muhammad Basheer (pp.56-60). Published at the Publication Division by the Secretary, National Council of Educational Research and Training, Sri Aurobindo Marg, New Delhi.