Why spokespeople fall apart on the last question

Picture the scene.
You are pretty sure your spokesperson is coming towards the end of their
media interview. You’re confident they have answered all the questions on
the topic well and you feel they have got the message across successfully.
Suddenly, the journalist asks something completely unexpected, completely
out of left field and your principal puts his foot straight into his mouth.
The final question has tripped up many a media spokesperson—and often
undone all of his or her p