Nellie is lucky Boris scratched his way out and escaped under the truck, otherwise he would have bit her hand. It's his defense mechanism.
What the post originally implied was that the actor Kevin Spacey's blood carried a mutated gene, but because Nellie interpreted it as a gorilla named Kevin, that really makes me want to give Boris a gorilla named Kevin. Like imagine, 4'9 little Boris walking around with a six foot gorilla on a leash named Kevin.