Coolest Doubt in Mahabharat

Coolest doubt in Mahabharat !!!!

In some remote village of India, one masterji is
teaching the Mahabharat katha to class 6 students.
He is at the 'krishnajanma' part of it.

Masterji: "Kansa heard the akashwani that his
sister's 8th child is going to kill him. He was
furious. He ordered to put vasudev n devki behind
the bars. First son is born, and kansa kills him by
poisoning... Second one is born n kansa throws him
off the mountain peak. Third one is born..."

Now Ramu, who is smartest of the lot, puts up his
hand. Masterji, I have a doubt (sounding nervous n
confused)

Masterji: "Ramu bete, whole India does not have
doubt in mahabharata then how come u have one?"

Ramu : Masterji, if Kansa knew that Devaki's 8th
child was going to Kill him, WHY THE HELL DID HE PUT
VASUDEV AND DEVAKI IN THE SAME CELL ?

Masterji faints......................... :)