Why do you think Bill Volt wasn't concerned about being in the monkey house? Do you think his opinion changed when Gene Johnson and sergeant Klages were afraid to touch things in his office?

Volt initially believed that the air ducts had something to do with the monkeys dying, especially after Dalgard came to examine them and mentioned the heat might be contributing to heat stress. We can assume, he changed his mind when Johnson and Klages arrived, as their behavior pointed to something far more serious.