Super Intelligent

3 toppers of IIT Delhi Mechanical Engg. were awarded a prize to Visit Dubai. They were caught by Police on doubt of shop lifting. Court awards death punishment to all. 3rd topper is brought to death platform and are given choices. Face up or face down? He chooses Face up. Face covered or open? "Open". "Brave!" Killer man is impressed and now presses button so that the blade falls on his neck. But, to the luck of Student, mechanism fails and blade does not fall. As per law of Dubai, he is let free. Now the second topper is called. He also chooses same options. This time also blade does not fall and he is also let free. Now is the turn of 1st topper ( the super intelligent mechanical engineer). He also chooses same options. Just before killer man was to press button, he asks him to stop. He says " that 3rd screw from top is loose. that is why blade is not falling"