Late tonight R. Kennedy invited me to come see him. We talked alone. The Cuban crisis, R. Kennedy began, continues to quickly worsen. We have just received a report that an unarmed American plane was shot down while carrying out a reconnaissance flight over Cuba. The military is demanding that the President arm such planes and respond to fire with fire.

“The USA can’t stop these flights, because this is the only way we can quickly get information about the state of construction of the missile bases in Cuba, which we believe pose a very serious threat to our national security. But if we start to fire in response—a chain reaction will quickly start that will be very hard to stop. The same thing in regard to the essence of the issue of the missile bases in Cuba. The USA government is determined to get rid of those bases-up to, in the extreme case, of bombing them, since, I repeat, they pose a great threat to the security of the USA. But in response to the bombing of these bases, in the course of which Soviet specialists might suffer, the Soviet government will undoubtedly respond with the same against us, somewhere in Europe. A real war will begin, in which millions of Americans and Russians will die. We want to avoid that any way we can, I’m sure that the government of the USSR has the same wish.”

Dobrynin’s Cable to the Soviet Foreign Ministry, October 27, 1962

According to the passage, what does Kennedy want to avoid and why? Do not 'copy' from the text. Put the answer in your own words.