Thankfully the zookeeper had common sense and prevented Tyson from becoming a Darwin award winner.
Tyson probably thought the gorilla would stand there and trade punches. That alone would have killed Mike.
What he probably didn't know is when gorillas fight, they bite. They have a bite force of 1300 PSI. That's
greater than a Lion,Tiger,Grizzly or Polar bear. They can easily decapitate a human simply by biting them.