"one of" is doing some heavy lifting there :)

That button isn't meant to stop crazy or evil people from killing us all. That's (hopefully) taken care of by things like careful pilot vetting.

A completely sane and non-mass-murderous pilot might still accidentally press a normal button. Especially if they were tired near the end of a long mission.

It's not as stringent as the safeguard that Roger Fisher proposed. He suggested that the nuclear launch codes be placed in a capsule and surgically implanted near the heart of a volunteer. That volunteer would follow the president around with a butcher knife. If the president ever wanted to launch the nukes it would need to be serious enough that he was willing to take that knife and carve the launch codes out of the chest of an innocent man.

We should put a piece of tape on the switch too. That'll really get the point across