Busdriver
Your account sounds like a bit of negligence. The engine start switch and the park brake move in different axes, the start switch moves forward/aft whereas the park brake rotates horizontally. That mistake is very basic and really does question the fundamentals of any switch or control movement. Clearly, it COULD happen to anyone, but SHOULDN'T, any control movement should be checked before operating it.
Still on topic, I must admit that I do prefer the Boeing philosophy (which I recall to be) of pressing the foot pedals and then applying the park brake to trap the pressure, rather than the Airbus philosophy of it being a switch - you have to be very careful applying the park brake on a 'bus when the ground crew ask you, ANY residual gspd will bring you to a very abrupt stop!