The PM simply isn't expecting it! Will take them by surprise and distract them from the key monitoring function.
Then he is going to get one hell of a surprise when something really serious happens on his watch if hasn't the cognitive capacity to switch off a FD switch in the one second it takes to do so. Jesus Wept. Has aviation got to the stage that we have to baby pilots that much, or are we so overwhelmed by the myriad of SOP's that are pushed down our throats in today's airline flying, that one slight item out of order is practically a Mayday situation?