What is Keller's responses to the accusations

Keller does not deny it; he ordered those cracked cylinder heads to be shipped out. Yet, they did not go into the type of plane that Larry flew. Chris says that Keller killed twenty-one men, and Chris then calls him a murderer. Keller explains that it was a matter of business: you work forty years, and in one moment, one failed shipment, the contracts can be torn up and you can lose everything. He thought that the military would notice the cracks anyway and that if they did not, he would warn them. But it was too late--the news was all over the papers that the planes had crashed, and the police were knocking on the door.