They were disappointed the employee wasn't cooperating? WTF...first, why don't they threaten him with jail time? Second, why is he even still an employee?
People severely overestimate how hard it is to kill everyone with nukes. You need a 15 megaton nuke(the largest nuke ever tested by the US) to take out just 1 island in hawaii. Just for reference "Fat man" was only 20 kilotons and would only take out about a 2km radius.
"Reports say he had been a source of concern for colleagues for 10 years, having confused emergency drills with real life incidents on at least two occasions."