HARRY: Let’s not make a fuss, Doctor.
DOCTOR: That Time Ring is our only hope of getting back to the TARDIS. Recovering it has got to be our number one priority. Do you understand, Harry? It’s vital.
HARRY: Yes, I know it’s vital, but we don’t want them to know that, do we?
Genesis of the Daleks. In which the Doctor flips-out and Harry has to be the voice of reason and calm him down