Thanks for the explanation.
Beware of explanations.
I haven't flown for a number of years now, and maybe things have changed, but when I flew transponders didn't have "squawk buttons." You just dialed in the code (four separate digit wheels) assigned by ATC. It's pretty hard to "accidentaly" dial in the hijack code unless one really intended to dial in the emergency code (7700, I think. And 7600 is used for something too.) instead.
ML/NJ